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VIROLOGY
INTRODUCTION
Virological tests are usually costly and labour-intensive, therefore they should
be undertaken only when good clinical indications for doing so exist, and after
thoughtful consideration of the types of tests to request for.
Virological tests fall into three categories:
• Culture of virus from infected body fluids or tissues
• Antibody detection in blood and, where appropriate, CSF
• Demonstration of the presence of viral antigen or viral nucleic acid in infected
tissues or body fluids.
SAMPLE LABELLING & COMPLETION OF REQUEST FORMS
All samples must be clearly labelled with the patient’s name and unique identification
number, e.g. NRIC number, as well as the nature, source and date of collection of the
sample.
Each sample must be accompanied by a request form that is completed legibly with the
patient’s name, unique identification number, location, relevant history, findings and
clinical diagnosis, the test(s) required, the nature, source and date of collection of the
sample, and the name and for urgent requests, the contact number of the requesting
doctor. The form must be signed by the requestor.
It should be ensured that these requirements are met to avoid rejection of the sample
by the laboratory or a delay in reporting.
GENERAL GUIDELINES FOR VIRUS ISOLATION
1. For most viral infections, the causative agents can only be isolated during the first
3 – 4 days of the acute illness.
2. Most viruses are slow growing and results may become available only after 1 – 3
weeks.
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SECTION 4: SAMPLE COLLECTION & HANDLING – SPECIAL INSTRUCTIONS & LAB TESTS
3. Viruses are usually very labile, so samples should reach the laboratory within
one hour of collection. If this is not possible, the sample must be refrigerated at
4°C (for a maximum period of 48 hours) until transport. Do not freeze samples
as many viruses are inactivated at –20°C. Within SGH, the telelift should not be
used for culture samples, as this will result in considerable delay in their reaching
the laboratory. For samples collected after office hours, refrigerate at 4°C until
transport to the laboratory. Do not freeze.
4. Transport the sample with an ice pack or in a bag of ice cubes. First seal the sample
in a plastic bag, then place this bag inside an outer plastic bag containing the ice
pack or ice cubes. On no account should the ice cubes come into direct contact
with the sample bottle as contamination will occur. Place the accompanying
request form into another plastic bag to keep the form dry.
5. All swabs and tissue samples for virus isolation must be transported in virus
transport medium (VTM). Dry swabs will not be accepted by the laboratory
because the virus would probably have died. Blood, CSF, stools and effusions may
be sent without VTM. For urine, see special instructions given below.
6. Swabs used for sampling should be made of cotton, dacron or rayon, not of calcium
alginate, and the shaft of the swab stick should preferably be made of plastic.
COLLECTION METHODS FOR VIRUS ISOLATION BY SAMPLE TYPE
THROAT SWABS
1. Swab the pharynx and both tonsils vigorously.
2. If the patient has an associated rhinitis, collect a nasal swab at the same time, using a
separate swab. Place both swabs in the same bottle of VTM.
NASOPHARYNGEAL ASPIRATES
Nasopharyngeal aspirates are superior to throat swabs for the recovery of viruses.
Further, immunofluorescence microscopy can be carried out on exfoliated cells in the
aspirate for rapid diagnosis.
1. Attach a disposable polythene catheter (French catheter 8 for infants) to a mucus
trap and a suction pump.
2. Insert the catheter through the nose for a distance equal to that from the tip of the
nose to the angle of the jaw.
3. Using the suction pump, aspirate mucus into the trap. If secretions are thick and
trapped in the catheter, dislodge the mucus by sucking up 1 – 3 mL of VTM.
4. Disconnect the trap when collection is complete and empty contents into a bottle
of VTM. (It may be necessary to pour the VTM into the mucus trap, swirl the
contents, then pour it back into the VTM bottle).
5. If a suction pump is not available, attach the catheter to a 20 mL syringe, aspirate
secretions, then expel secretions into VTM.
SALIVA
For mumps isolation, swab the buccal mucosa opposite the upper molars where
Stensen’s ducts open, then swab the floor of the mouth at the openings of the
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VIROLOGY
submandibular gland ducts. For cytomegalovirus (CMV) isolation, swab the buccal
mucosa or aspirate saliva into a mucous trap and send in VTM.
VESICULAR LESIONS
Sample fresh skin vesicles during the first three days following the appearance of the
eruption. Crusted lesions have a lower chance of yielding viable virus. Macules or
papules should not be sampled.
1. Gently clean the surface of the vesicle with sterile saline. Do not use alcohol.
2. If the vesicle is intact, use a sterile needle to lift off the roof of the vesicle.
3. Using a sterile swab, soak up all the fluid from the vesicle, then swab the base of the
lesion vigorously to dislodge cells on the base (which contain the virus) onto the swab.
4. Using the same swab, repeat the procedure with a number of vesicles, if present,
in order to increase the yield of virus.
5. Insert the swab into a bottle of VTM, break off the stick and screw-cap the bottle tightly.
OPEN LESIONS
Clean open lesions on the skin and genitalia with sterile saline to remove any pus, then
swab firmly to sample the basal cells. For oral lesions, swab the base of the lesions. Insert
the swab into a bottle of VTM, break off the stick and screw-cap the bottle tightly.
For keratoconjunctivitis, scrapings from lesions must be sent for virus isolation and/
or immunofluorescence.
CONJUNCTIVAL SWABS
Using a swab moistened with sterile saline, pull down the lower lid and swab the
conjunctiva firmly, then evert the upper lid and swab similarly. Insert the swab into a
bottle of VTM, break off the stick and screw-cap the bottle tightly.
For keratoconjunctivitis, scrapings from lesions must be sent for virus isolation and/
or immunofluorescence.
CERVICAL SWABS
1. Use a speculum during collection.
2. Use one swab to clean the cervix of mucus and discard.
3. Insert a second swab about 1 cm into the cervical canal.
4. Rotate and leave for a few seconds to absorb the secretions.
5. If vesicles or open lesions are present, sample as described above in Collection
Methods for Virus Isolation by Sample Type (Virology Section, Vesicular
Lesions and Open Lesions).
6. Transport in VTM.
BIOPSY AND AUTOPSY SAMPLES
Fresh samples have to be sent for virus isolation. Formalinised or fixed tissues cannot
be used, as the virus would have been destroyed. Place a piece of the sample about 1 cm
in size (or smaller if necessary) directly into the bottle of VTM, and send immediately
to the laboratory on ice.
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SECTION 4: SAMPLE COLLECTION & HANDLING – SPECIAL INSTRUCTIONS & LAB TESTS
URINE
For adults, instruct the patient to clean the urethral/vulval and perineal areas with
soap and water, then to collect a mid-stream sample in a sterile bottle. For infants and
young children, clean the perineum and genitalia and collect the sample in a sterile
bottle. Transfer the urine into the urine culture bottle up to the mark indicated
(about 10 mL). This bottle, which contains antibiotics, can be obtained from the
Client Services Section of the Department of Pathology.
STOOLS
Stools should be sent for the diagnosis of enteroviral infections. In enteroviral
infections, virus is excreted in the faeces for several weeks, so stools can be collected
after the first week of illness if a diagnosis is required at that stage.
Most of the gastroenteritis-causing viruses such as rotavirus, the enteric adenoviruses
and the caliciviruses cannot be cultured in tissue cultures at present, and virus
isolation is usually non-productive for viral gastroenteritis.
With CMV enteritis, stool cultures are usually negative and an intestinal biopsy
sample is required for virus isolation or antigen detection.
Stools in amount equivalent to the tip of the little finger should be collected in a
sterile bottle without VTM.
RECTAL SWABS
Collect from cases with suspected enteroviral infections only when stools are difficult
to collect, as rectal swabs are inferior to stools.
Insert a sterile swab into the anal orifice, (at least 3 cm deep in an adult) and rotate to
ensure collection of faeces. Place swab in a bottle of VTM, break off swab stick and
screw-cap firmly.
BLOOD
Viruses may be isolated from leucocytes and/or plasma so unclotted blood must be
sent.
1. Collect 6 mL blood into EDTA tubes. (EDTA is to be preferred to heparin as an
anticoagulant because some viruses may be inactivated by heparin).
2. Mix the sample gently to prevent clotting and lysis of cells.
3. Do not freeze the sample during transport as this will cause cell lysis.
CSF
1 – 2 mL CSF should be collected in a sterile bottle without VTM.
EFFUSIONS
Collect 3 – 4 mL of fluid in a sterile bottle without VTM.
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GENERAL GUIDELINES FOR VIRUS SEROLOGY
1. Collect 3 – 5 mL of plain blood for serology (6 – 8 mL if a panel of tests is being
ordered). Introduce into a screw-capped container, without anticoagulants,
and send the sample to the laboratory inside a sealed plastic bag. If any delay is
anticipated, the sample must be refrigerated at 4°C until transport. Do not freeze
as this will cause lysis of the cells, resulting in possible interference with some
serological tests.
2. To demonstrate a significant rise in antibody levels, the acute sample should be
collected as soon as possible after the onset and the second sample 10 days to two
weeks later, and not earlier than seven days. When sending the second sample,
label the sample as “second”. The two samples will then be tested in parallel in the
same test run.
3. Tests must be requested by name as well as methodology, if more than one type
of test is offered (e.g. rubella EIA* or rubella HI†). If in doubt about what to ask
for, consult the laboratory.
4. Where an urgent result is required, the first serum can be tested for IgM
antibody. However, even IgM antibody may be absent in a sample collected
within 1 – 3 days of the onset, and a second sample taken seven days later will be
required to test for IgM. False negative IgM results can also occur, especially in
infants with congenital infections (e.g. CMV, HIV). Conversely, false positive IgM
antibody results can occur in patients with rheumatoid factor, collagen diseases
or, sometimes, with other viral infections.
5. Great care must be taken not to send a traumatised, blood-stained CSF sample, as
interpretation will be difficult. The antibody detected may merely represent that
present in the blood. When sending CSF, always collect a blood sample at the
same time, as this will be useful for determining the significance of any antibody
detected in the CSF.
6. For immunity screening, a single sample will suffice. Results are given as antibody
“Present” or “Absent”, or in the case of hepatitis B and rubella antibody, in
international units. The complement fixation test (CFT) should not be requested
for immunity screening because complement fixing antibody is not long lasting.
7. Serology for enteroviral infections is not available from this laboratory. For
diagnosis, isolation must be carried out (see under Enterovirus Isolation).
8. For Rubella Serology on female patients suspected of having acute rubella or who
are contacts of rubella cases, an additional form giving clinical details and LMP
(last menstrual period) dates must be filled in.
* EIA: Enzyme Immunoassay † HI: Haemagglutination-inhibition
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SECTION 4: SAMPLE COLLECTION & HANDLING – SPECIAL INSTRUCTIONS & LAB TESTS
GENERAL GUIDELINES FOR VIRAL ANTIGEN DETECTION
1. The direct detection of viral antigen in secretions and tissues is very useful for
the rapid diagnosis of viral infections, as direct antigen detection may give results
within one and a half to two hours. However, a negative result by antigen detection
may still be followed by a positive result by culture. It is therefore useful to send
samples in viral transport medium, so that both antigen detection and isolation
can be carried out at the same time.
2. Where both culture and antigen detection are required, samples must be sent
in VTM. If only antigen detection is required, the sample can be sent in a clean
bottle with 1 – 2 mL of sterile saline added. Place the container in a sealed plastic
bag for despatch to the laboratory. If delay is anticipated, refrigerate at 4°C but do
not freeze as this will cause cell lysis, making antigen detection impossible.
3. The types of samples that can be sent for antigen detection include:
(a) respiratory secretions such as nasopharyngeal aspirates, bronchoalveolar
lavage and sputum (throat swabs are unsuitable because of the sparsity of
respiratory epithelial cells in such samples)
(b) fluids from skin vesicles, pericardial and pleural fluid
(c) scrapings from the base of vesicle or open skin lesions or the conjunctivae
(d) body fluids such as urine and CSF
(e) white cells in blood (for CMV)
(f ) biopsy or autopsy tissue samples
A SUMMARY OF TESTS AND SAMPLES TO COLLECT FOR VIRAL INFECTIONS
Presentation Possible Samples for Samples for Samples
pathogens isolation serology for antigen
detection
Respiratory Influenza, RSV, TS, NPA or BAL, Paired sera for NPA or BAL
infection rhinovirus, lung biopsy, CFT (all except (all except
adenovirus, ETTA in VTM. rhinoviruses, rhinovirus,
parainfluenza, Pleural fluid enteroviruses, enterovirus,
CMV, VZV, HSV, without VTM SARS-CoV). SARS-CoV)
enteroviruses, Serum for SARS-
SARS-CoV CoV total antibody
EIA, and IgM and
IgG
Neurological Enteroviruses, CSF, stool, NPA, Paired sera and NPA for
diseases mumps, measles, brain biopsy. CSF for CFT, measles,
(meningitis, HSV, VZV, JE, (VTM for NPA (excluding HIV mumps; Vesicle
encephalitis, HIV and biopsy & enteroviruses), swab for
paralysis) sample) acute serum HSV,VZV; Brain
for IgM (except biopsy for HSV,
JE, entero), one VZV, measles,
serum for HIV mumps
EIA
Conjunctivitis, Adenovirus, Conjunctival Single serum for Conjunctival
keratocon- coxsackie A24, swab or scraping VZV IgM; paired scraping for
junctivitis enterovirus 70, in VTM sera for VZV, HSV HSV, VZV,
HSV, VZV and Adeno CFT adenovirus
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VIROLOGY
Presentation Possible Samples for Samples for Samples
pathogens isolation serology for antigen
detection
Viral STD HSV, HIV Penile, vaginal or Paired sera for Swab or
cervical swab in CFT for HSV. scraping from
VTM for HSV Single serum for lesion in saline
HIV EIA for HSV
Maculopapular Measles, rubella, Enteroviruses: Measles and Measles: NPA
rashes dengue, HIV, throat swab in rubella: Acute for antigen
enteroviruses, VTM and stools. serum for IgM detection
parvovirus B19 Dengue: Blood and paired sera
Measles: NPA, for HI or CFT.
TS, sputum in Dengue: see under
VTM, urine “Dengue” heading
below. HIV: EIA
or PA Parvo. B19:
single serum for
IgG and IgM EIA
Vesicular skin HSV, VZV, Swab and fluid Paired sera for Swab or
lesions enteroviruses from lesion in CFT (HSV and scraping from
VTM VZV only) lesion for HSV
and VZV
Cardiovascular: Enteroviruses, Throat swabs For influenza: For influenza:
myo- or influenza and NPA in paired sera for NPA for antigen
pericarditis, VTM, stools CFT
pleurodynia (enteroviruses
only), periocardial
fluid
Hepatitis HAV, HBV, HCV, CMV: as below CMV: as below. CMV: as below
HDV, HEV, CMV, EBV: one serum
EBV for IgM. Rest: one
serum for EIA
Gastroenteritis Rotavirus, Intestinal biopsy Paired sera for Stool for
norovirus, for CMV in CFT (CMV and rotavirus and
adenovirus, VTM. Stool for adenovirus) norovirus
CMV, enterovirus enteroviruses, antigen
(infants) and adenoviruses
others
Parotitis Mumps virus Saliva, urine Single serum for NPA, urine
IgM. Paired sera or saliva for
for CFT mumps antigen
CMV Infection CMV Saliva, NPA, Paired sera for Blood, BAL,
BAL, biopsy in CFT, acute serum biopsy tissue,
VTM, blood, for IgM or urine
urine
Dengue Dengue types Blood Serum for IgM Blood
1–4 EIA
Note: Bold type indicates preferred samples and test.
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SECTION 4: SAMPLE COLLECTION & HANDLING – SPECIAL INSTRUCTIONS & LAB TESTS
BAL : broncho-alveolar lavage
CFT : complement fixation test
CMV : cytomegalovirus
EBV : Epstein-Barr virus
EIA : enzyme immunoassay
ETTA : endotracheal tube aspirate
HAV : hepatitis A virus
HBV : hepatitis B virus
HCV : hepatitis C virus
HDV : hepatitis D (or delta) virus
HEV : hepatitis E virus
HI : haemagglutination-inhibition
HIV : human immunodeficiency virus
HSV : herpes simplex virus
IF : immunofluorescence
JE : Japanese encephalitis virus
LCM : lymphocytic choriomeningitis virus
NPA : nasopharyngeal aspirate
RSV : respiratory syncytial virus
SARS-CoV : severe acute respiratory syndrome coronavirus
STD : sexually transmitted diseases
TS : Throat swab
VTM : viral transport medium
VZV : varicella-zoster virus
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VIROLOGY
ALPHABETICAL TEST LISTING – VIRUS ISOLATION
ADENOVIRUS ISOLATION
Specimen required : Urine in cases of cystitis
Nasopharyngeal aspirate, brochoalveolar lavage, sputum,
endotracheal tube aspirate, throat swab in respiratory disease
Conjunctival swab or scraping in conjunctivitis or
keratoconjunctivitis
(See also Virology Sections, General Guidelines for Virus
Isolation & Collection Methods for Virus Isolation by
Sample Type.)
Method : Tissue culture
Test results : Reported as positive/negative
Turnaround time : Positive report with typing results : 2 – 6 weeks
Negative report : 21 days
Day(s) test set up : Monday – Saturday
CYTOMEGALOVIRUS ISOLATION
Specimen required : 6 mL unclotted blood in EDTA bottle for all clinical
presentations, except congenital infections and
gastroenteritis
Urine for all clinical presentations
Saliva, sputum, nasopharyngeal aspirate or bronchoalveolar
lavage for pneumonia
Saliva and urine for congenital infections
Intestinal biopsy for gastroenteritis
Other biopsy samples (e.g. lymph node, liver)
Uterine curetting
(See also Virology Sections, General Guidelines for Virus
Isolation & Collection Methods for Virus Isolation by
Sample Type.)
Refrigerate samples until transport to laboratory. Do not
freeze.
Method : Tissue culture
Test results : Reported as positive/negative
Turnaround time : Positive report : 2 days – 3 weeks
Negative report : 21 days
Day(s) test set up : Monday – Saturday
DENGUE VIRUS ISOLATION
Specimen required : 3 – 5 mL plain blood or 6 mL unclotted blood in EDTA
bottle within 1 week of illness
Where clinically indicated, 1 – 2 mL CSF in sterile bottle
(See also Virology Sections, General Guidelines for Virus
Isolation & Collection Methods for Virus Isolation by
Sample Type.)
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Method : Tissue culture
Test results : Reported as positive/negative
Turnaround time : Positive report : 8 days
Negative report : 7 days
Day(s) test set up : Monday – Saturday
ENTEROVIRUS ISOLATION
Specimen required : 1 – 2 mL CSF in sterile bottle for neurological diseases
Stool for all clinical presentations. Two stool samples within
48 hours of each other must be sent from all patients aged
15 years and below with a diagnosis of AFP (acute flaccid
paralysis) for poliomyelitis surveillance.
Throat swab/nasopharyngeal aspirate within the first 3 – 4
days of onset for all clinical presentations
Throat swab, nasopharyngeal aspirate or bronchoalveolar
lavage for respiratory infections
Pericardial fluid for pericarditis
Vesicular fluid for vesicular eruptions
(See also Virology Sections, General Guidelines for Virus
Isolation & Collection Methods for Virus Isolation By
Sample Type.)
Refrigerate samples until transport to laboratory. Do not
freeze.
Method : Tissue culture
Test results : Reported as positive/negative
Turnaround time : Positive preliminary report : 2 days – 3 weeks
Final report with enterovirus typing results : 2 – 8 weeks
Negative report : 3 weeks
Day(s) test set up : Monday – Saturday
HERPES SIMPLEX VIRUS ISOLATION
Specimen required : Swabs or scrapings from vesicles on skin, mouth or
genitalia
CSF (1 – 2 mL) in sterile bottle for neurological diseases
Conjunctival swab or scraping for eye infections
Brain biopsy for encephalitis
(See also Virology Sections, General Guidelines for Virus
Isolation & Collection Methods for Virus Isolation by
Sample Type.)
Refrigerate samples until transport to laboratory. Do not
freeze.
Method : Tissue culture
Test results : Reported as positive/negative
Turnaround time : Positive report : 1 – 7 days
Negative report : 7 days
Day(s) test set up : Monday – Saturday
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VIROLOGY
INFLUENZA VIRUS ISOLATION
Specimen required : Throat swab, sputum, endotracheal tube aspirate but
preferably nasopharyngeal aspirate or bronchoalveolar
lavage
Biopsy/autopsy lung tissue
(See also Virology Sections, General Guidelines for Virus
Isolation & Collection Methods for Virus Isolation by
Sample Type.)
Refrigerate samples until transport to laboratory.
Method : Tissue culture
Test results : Reported as positive/negative
Turnaround time : Positive report : 5 – 21 days
Negative report : 21 days
Day(s) test set up : Monday – Saturday
MEASLES VIRUS ISOLATION
Specimen required : Nasopharyngeal aspirate/wash, throat/nasopharyngeal
swabs, sputum
Urine in urine culture tube
Method : Tissue culture
Test results : Reported as positive/negative
Turnaround time : Positive report : 2 – 14 days
Negative report : 14 days
Day(s) test set up : Monday-Saturday
MUMPS VIRUS ISOLATION
Specimen required : Saliva in virus transport medium
Urine in urine culture bottle
CSF (in cases of meningitis) in sterile bottle
(See also Virology Sections, General Guidelines for Virus
Isolation & Collection Methods for Virus Isolation by
Sample Type.)
Method : Tissue culture
Test results : Reported as positive/negative
Turnaround time : Positive report : 7 – 21 days
Negative report : 21 days
Day(s) test set up : Monday – Saturday
NEUROTROPIC VIRUS PANEL ISOLATION
Viruses to be expected : Herpes simplex, measles, mumps and enterovirus
encephalitis viruses. Varicella-zoster virus, although not
included in the panel, can also be requested.
Specimen required : CSF (1 – 2 mL) in sterile bottle
Method : Tissue culture
Test results : Reported as positive/negative
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Turnaround time : Positive report : 2 – 21 days
Negative report : 7 days for herpes simplex virus, 14 days
for measles virus, 21 days for mumps
and enterovirus
Day(s) test set up : Monday – Saturday
RESPIRATORY VIRUS ISOLATION
Viruses to be expected : Influenza A and B, respiratory syncytial virus
(especially in infants and young children), parainfluenza
viruses, rhinovirus, adenovirus, SARS coronavirus,
cytomegalovirus, enteroviruses, varicella-zoster virus
Specimen required : Throat swab, sputum, endotracheal tube aspirate but
preferably nasopharyngeal aspirate or bronchoalveolar
lavage
Biopsy/autopsy lung tissue
(See also Virology Sections, General Guidelines for Virus
Isolation & Collection Methods for Virus Isolation by
Sample Type.)
Refrigerate samples until transport to laboratory. Do not
freeze.
Method : Tissue culture
Test results : Reported as positive/negative
Turnaround time : Positive report : 5 – 21 days
For enterovirus – final report
with enterovirus typing results : 2 – 8 weeks
Negative report : 21 days
Day(s) test set up : Monday – Saturday
SARS CORONAVIRUS ISOLATION
Specimen required : Nasopharyngeal aspirate, endotracheal aspirate or
bronchoalveolar lavage prefereable. Sputum, throat swab
Biopsy/autopsy lung, brain, heart tissue
(See also Virology Sections, General Guidelines for Virus
Isolation & Collection Methods for Virus Isolation by
Sample Type.)
Method : Tissue culture
Test results : Reported as positive/negative
Turnaround time : Positive report : 7 – 21 days
Negative report : 21 days
Day(s) test set up : Monday – Saturday
VARICELLA ZOSTER VIRUS ISOLATION
Specimen required : Swabs or scrapings from vesicles on skin
CSF (1 – 2 mL) in sterile bottle for neurological presentation
Conjunctival swab or scraping for ophthalmic zoster
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Nasopharyngeal aspirate, sputum or bronchoalveolar lavage
or pneumonia
(See also Virology Sections, General Guidelines for Virus
Isolation & Collection Methods for Virus Isolation by
Sample Type.)
Refrigerate samples until transport to laboratory. Do not
freeze.
Method : Tissue culture
Test results : Reported as positive/negative
Turnaround time : Positive report : 2 – 14 days
Negative report : 14 days
Day(s) test set up : Monday – Saturday
VIRUS ISOLATION IN CARDIAC DISEASES
Viruses to be expected : Enteroviruses, influenza viruses
Sample Required : Stool for enteroviruses
Throat swab, nasopharyngeal aspirate during the first 3 – 4
days of onset
Pericardial fluid for pericarditis
(See also Virology Sections, General Guidelines for Virus
Isolation & Collection Methods for Virus Isolation by
Sample Type.)
Refrigerate samples until transport to laboratory. Do not
freeze.
Method : Tissue culture
Test results : Reported as positive/negative
Turnaround time : Positive report
– Influenza : 1 – 2 weeks
– Enteroviruses : 2 days – 3 weeks (preliminary)
2 – 8 weeks for final report with
enterovirus typing results
Negative report : 3 weeks
Day(s) test set up : Monday – Saturday
VIRUS ISOLATION IN NEUROLOGICAL INFECTIONS
Viruses to be expected : Enteroviruses, mumps, herpes simplex, varicella-zoster and
influenza viruses
Specimen required : Throat swab, nasopharyngeal aspirate during the first 3 – 4
days of the illness
Stools
CSF
Swabs or scrapings of vesicles if present
Saliva (instead of throat swab or nasopharyngeal aspirate)
and urine if mumps suspected
Brain biopsy for herpes encephalitis
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(See also Virology Sections, General Guidelines for Virus
Isolation & Collection Methods for Virus Isolation by
Sample Type.)
Refrigerate samples until transport to laboratory. Do not
freeze.
Method : Tissue culture
Test results : Reported as positive/negative
Turnaround time : Positive report : 1 – 21 days
For enteroviruses – final report
with enterovirus typing results : 2 – 8 weeks
Negative report : 21 days
Day(s) test set up : Monday – Saturday
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VIROLOGY
ALPHABETICAL TEST LISTING – VIRUS SEROLOGY
CHLAMYDIA GROUP TOTAL ANTIBODY
Specimen required : 3 – 5 mL plain blood. Do not freeze. Send paired sera
taken two weeks apart for rising titre.
Method : Complement Fixation Test (CFT)
Test results : Significant result: ≥ 4 fold rise by CFT in paired sera
Turnaround time : 1 – 6 days after acute or convalescent serum is received
Day(s) test set up : Tuesday and Thursday
COXIELLA BURNETII TOTAL ANTIBODY
Specimen required : 3 – 5 mL plain blood. Do not freeze. Send paired sera
taken two weeks apart for rising titre.
Method : Complement Fixation Test (CFT)
Test results : Significant result: ≥ 4 fold rise by CFT in paired sera
Turnaround time : 1 – 6 days after acute or convalescent serum is received
Day(s) test set up : Tuesday and Thursday
CYTOMEGALOVIRUS (CMV) ANTIBODY
• Cytomegalovirus IgM Antibody (anti-CMV IgM)
• Cytomegalovirus IgG Antibody (anti-CMV IgG)
• Cytomegalovirus CF Total Antibody (anti-CMV total)
Specimen required : 3 – 5 mL plain blood. Do not freeze.
(a) To diagnose acute infection, send acute sample for
CMV IgM Antibody and second serum taken 14 days
later for CMV CF Total Antibody on the pair.
(b) To diagnose previous infection, send single sample for
CMV IgG Antibody.
Method : Anti-CMV IgM : Enzyme Immunoassay &
Immunofluorescence
Anti-CMV IgG : Microparticle Enzyme
Immunoassay
Anti-CMV total : Complement Fixation Test
(CFT)
Test results : Acute infection : IgM Ab positive and/or
paired sera showing ≥ 4 fold
rise of CF Ab titres
Single sample having CF Ab
titre ≥ 128 is suggestive of an
acute infection. Confirm by
virus isolation.
Previous (latent) infection : CMV IgG present.
Turnaround time : 1 – 8 days
Day(s) test set up : Anti-CMV IgM : Monday
Anti-CMV IgG : Tuesday and Friday
Anti-CMV total : Tuesday and Thursday
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SECTION 4: SAMPLE COLLECTION & HANDLING – SPECIAL INSTRUCTIONS & LAB TESTS
DENGUE VIRUS ANTIBODY
• Dengue IgM antibody (anti-Dengue IgM)
• Dengue Total HI antibody (anti-Dengue total)
Specimen required : 3 – 5 mL plain blood. Do not freeze.
To diagnose acute infection, send acute sample for dengue
IgM antibody and a second sample taken 7 – 10 days later
for dengue IgM and dengue HI antibody on the pair.
Method : Anti-Dengue IgM : Enzyme immunoassay
Anti-Dengue total : Haemagglutination inhibition
Test results : Acute infection : IgM antibody positive on acute
serum or paired sera showing
seroconversion
Paired sera showing significant rise
of HI antibody titers
Turnaround time : Anti-dengue IgM : 2 – 5 days
Anti-dengue total : 2 – 8 days
Day(s) test set up : Anti-Dengue IgM : Monday, Wednesday and Friday
Anti-Dengue total : Once a week
EPSTEIN-BARR VIRUS (EBV) ANTIBODY
• Epstein-Barr virus VCA IgM Antibody (anti-VCA IgM)
• Epstein-Barr virus VCA IgG Antibody (anti-VCA IgG)
Specimen required : 3 – 5 mL plain blood. Do not freeze.
(a) To diagnose acute infection, send single sample for EBV
VCA IgM Antibody and second serum taken 10 – 14 days
later if indicated.
(b) To diagnose previous infection, send single sample for
EBV VCA IgG Antibody.
Method : Immunofluorescence
Test results : Acute infection : EBV VCA IgM positive
or paired sera showing
seroconversion
Previous (latent) infection : EBV VCA IgG positive
Turnaround time : Anti-VCA IgM/IgG : 1 – 4 days
Day(s) test set up : Tuesday and Friday
HANTAVIRUS TOTAL ANTIBODY
Specimen required : 3 – 5 mL plain blood. Do not freeze.
To diagnose acute infection, send paired sera taken two
weeks apart for Hantavirus total Ab.
Method : Immunofluorescence
Test results : Acute infection : Paired sera showing ≥ 4 fold rise of
total Ab titres
Turnaround time : 1 – 4 days
Day(s) test set up : Tuesday and Friday
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VIROLOGY
HEPATITIS A VIRUS (HAV) ANTIBODY
• Hepatitis A IgM Antibody (anti-HAV IgM)
• Hepatitis A Total Antibody (anti-HAV total)
Specimen required : 3 – 5 mL plain blood. Do not freeze.
(a) To diagnose acute infection, send one sample for anti-
HAV IgM.
(b) To diagnose previous infection and immunity, send one
sample for anti-HAV total Ab.
Method : Microparticle Enzyme Immunoassay (for anti-HAV total Ab)
Chemiluminescent Microparticle Immunoassay (for anti-HAV IgM)
Test results : Acute infection : IgM positive
Past infection : Total Ab positive, IgM negative
Turnaround time : Anti-HAV IgM : 1 – 2 days
Anti-HAV Total : 1 – 3 days
Day(s) test set up : Anti-HAV IgM : Monday – Saturday
Anti-HAV Total : Monday – Friday
HEPATITIS B VIRUS SEROLOGY
• Hepatitis B Surface Antigen (HBsAg)
• Antibody to Surface Antigen (anti-HBs)
• IgM Antibody to Core Antigen (anti-HBc IgM)
• Antibody to Core Antigen (anti-HBc total)
• Hepatitis B ‘e’ Antigen (HBeAg)
• Antibody to e Antigen (anti-HBe)
• Confirmatory Test for HBsAg
Specimen required : 3 mL plain blood for single marker
6 – 8 mL plain blood for panel of markers
Do not freeze.
(a) To diagnose acute hepatitis B infection or the carrier
state, send blood for HBsAg and anti-HBc IgM.
(b) To determine immune status following past infection or
vaccination, send blood for anti-HBs.
(c) In a carrier, send blood for HBeAg and anti-HBe.
Method : Chemiluminescent Microparticle Immunoassay (for all above)
Test results
HBsAg Anti-HBs Anti-HBc Anti-HBc HBeAg Interpretation
IgM total
+ or – <10 mIU/mL + + + or – Acute Hepatitis B
+ <10 or ≥ 10 – + + or – Hep B carrier
mIU/mL
– ≥ 10 mIU/mL – + – Past Infection*
– ≥ 10 mIU/mL – – – Vaccination*
* An anti-HBs antibody level >10 mIU/mL is considered to be protective.
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SECTION 4: SAMPLE COLLECTION & HANDLING – SPECIAL INSTRUCTIONS & LAB TESTS
Turnaround time : HBsAg or anti-HBs : 1 – 2 days
Anti-HBc IgM or Anti-HBc total : 1 – 3 days
HBeAg or anti-HBe : 1 – 3 days
Confirmatory HBsAg : 1 – 7 days
Hepatitis B panels : 1 – 3 days
Day(s) test set up : HBsAg and anti-HBs : Monday – Saturday
Anti-HBc IgM and Anti-HBc total : Monday, Wednesday
and Friday
HBeAg and anti-HBe : Monday – Friday
Confirmatory HBsAg : Once a week
HEPATITIS C VIRUS (HCV) SEROLOGY
• Hepatitis C Virus Antibody (anti-HCV IgG)
• Anti-HCV Supplemental Assay (anti-HCV RIBA)
Specimen required : 5 mL plain blood. Do not freeze.
(a) The Supplemental Assay is only carried out to
determine whether the screening test is a true positive
or not. Do not order Supplemental Assay if anti-HCV
IgG is nonreactive.
(b) If the first sample is negative for hepatitis A, B and C
markers, send a second sample 3 – 6 months later for
anti-HCV IgG to exclude acute HCV infection.
Method : Anti-HCV IgG : Chemiluminescent Microparticle
Immunoassay
Anti-HCV RIBA : Strip Immunoassay
Test results : See Laboratory report for result interpretation.
Turnaround time : Anti-HCV IgG : 1 – 2 days
Anti-HCV RIBA : 2 – 15 days
Day(s) test set up : Anti-HCV IgG : Monday – Saturday
Anti-HCV RIBA : Every other Tuesday
HEPATITIS DELTA VIRUS ANTIBODY (ANTI-HDV TOTAL AB)
Specimen required : 3 – 5 mL plain blood. Do not freeze.
Method : Enzyme Immunoassay
Test results : A positive test result must be interpreted in conjunction with
the clinical features of the patient and the test results for HBV
markers.
Turnaround time : 1 – 8 days
Day(s) test set up : Wednesday
HEPATITIS E VIRUS (HEV) ANTIBODY
• Hepatitis E IgM Antibody (anti-HEV IgM)
• Hepatitis E IgG Antibody (anti-HEV IgG)
In acute HEV infection, both IgM and IgG tests are recommended
Specimen required : 3 – 5 mL plain (clotted) blood. Do not freeze.
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VIROLOGY
Method : Enzyme Immunoassay for both above
Test results : Acute infection : IgM positive
Past infection : IgG positive, IgM negative
Turnaround time : Negative report : 1 – 14 days
Positive report : 16 – 30 days
Day(s) test set up : Every other Wednesday
HEPATITIS, VIRAL – PANEL TESTS
• Hepatitis, Acute Viral Screen
Specimen required : 6 – 8 mL plain blood. Do not freeze.
To diagnose acute hepatitis A and B infections, send blood
for anti-HAV IgM, HBsAg and anti-HBc IgM.
Method : Chemiluminescent Microparticle Immunoassay
Test results
Anti-HAV IgM HBsAg Anti-HBc IgM Interpretation
+ – – Acute type A hepatitis
+ + or – + Acute type B hepatitis
+ + – Acute type A hepatitis in a
hepatitis B carrier
– – – Non-A, Non-B hepatitis
Turnaround time : 1 – 2 days
Day(s) test set up : See serological tests for hepatitis A and B.
• Hepatitis B Screen (HBsAg + anti-HBs or anti-HBc IgM)
Specimen required : 6 – 8 mL plain blood. Do not freeze.
Hepatitis B screen: To test for present or past hepatitis
B infection. The serum will first be tested for HBsAg. If
HBsAg is negative, serum will be quantitatively tested for
anti-HBs. If HBsAg is positive, it will be tested for anti-HBc
IgM instead.
Method : Chemiluminescent Microparticle Immunoassay
Test results
HBsAg Anti-HBs Anti-HBc IgM Interpretation
– <10 mIU/mL Not tested Non-immune to hepatitis B
– ≥ 10 mIU/mL Not tested Antibody present: immune if
level >10 mIU/mL
+ Not tested + Acute type B hepatitis
+ Not tested – Possible hepatitis B carrier
Turnaround time : 1 – 3 days
Day(s) test set up : See Serological tests for hepatitis B.
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SECTION 4: SAMPLE COLLECTION & HANDLING – SPECIAL INSTRUCTIONS & LAB TESTS
HERPES SIMPLEX VIRUS (HSV) ANTIBODY
• Herpes Simplex IgM Antibody (anti-HSV IgM)
• Herpes Simplex Virus CF Antibody (anti-HSV total)
Specimen required : 3 – 5 mL plain blood. Do not freeze.
(a) To diagnose acute infection, send acute sample for
herpes simplex IgM antibody and a second serum
taken 14 days later for herpes simplex CF antibody on
the pair.
(b) For transplant patients, to determine baseline HSV titres,
send single sample for herpes simplex CF antibody.
Note : Wherever possible, send samples for virus isolation for the
diagnosis of herpes simplex virus infections.
Method : Anti-HSV IgM: Immunofluorescence
Anti-HSV total: Complement Fixation Test
Test results : Primary or First Episode Genital Herpes:
HSV IgM positive and ≥ 4 fold rise in total antibody. CF
(total) Ab will be absent or low (<16) in first sample.
Reactivation:
IgM usually negative. ≥ 4-fold rise in total Ab
CF (total) Ab will be present in first sample.
Previous (latent) Infection:
Total Ab present in the absence of IgM Ab and symptoms.
Turnaround time : Anti-HSV IgM : Urgent cases : 3 – 4 hrs
Routine cases : 1 – 4 days
Anti-HSV total : 1 – 6 days after acute or convalescent
serum is received
Day(s) test set up : Anti-HSV IgM : Urgent cases : Stat
Routine cases : Tuesday and Friday
Anti-HSV total : Tuesday and Thursday
HUMAN IMMUNODEFICIENCY VIRUS (HIV) ANTIBODY, SCREENING (includes
Confirmation if reactive)
Specimen required : 5 mL plain blood. Samples must be double bagged using a
plastic bag labelled “Biohazard”.
Method : Microparticle Enzyme Immunoassay (MEIA), Particle
Agglutination (PA)
Rapid Tests in urgent situations. Rapid Tests are reported as
“presumptive” and are followed by other screening methods.
For confirmation, methods include another MEIA/EIA, PA,
line immunoassay and/or Western Blot.
Test results : Reported as Reactive or Non-Reactive
Turnaround time : Stat screening : 1 hour
Routine screening non-reactive report : 1 – 2 days
Confirmation of reactive results : 2 – 10 days
Day(s) test set up : Screening : Monday – Saturday
Also stat outside office hours for potential organ donors
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VIROLOGY
HUMAN IMMUNODEFICIENCY VIRUS (HIV) ANTIBODY, WESTERN BLOT
Specimen required : 5 mL plain blood. Samples must be submitted by a referring
laboratory and accompanied by screening results unless
special indications exist, e.g. for research or life insurance.
Method : Western Blot
Test results : HIV status confirmed if there are:
(a) Any 2 of p24, gp41, gp120/160 (CDC criteria)
OR
(b) 2 of 3 env bands with or without gag and/or pol bands
(WHO criteria)
Indeterminate result:
Bands are present that do not meet Positive criteria. Patients
should be retested 4 weeks to 6 months later, as indicated on
the individual test report; sample should be accompanied by
previous test result and laboratory reference number.
Inconclusive result:
Band profile cannot be definitely characterised as
positive, negative or indeterminate. Such a report is
accompanied by a request for a second blood sample to
be sent 6 weeks later.
Turnaround time : 2 – 10 days
Day(s) test set up : Monday
MEASLES ANTIBODY
• Measles IgM or IgG Antibody (anti-Measles IgM or IgG)
• Measles Total CF Antibody (anti-Measles total)
Specimen required : 3 – 5 mL plain blood. Do not freeze.
(a) To diagnose acute measles infection, send single acute
sample for IgM antibody and a second serum taken two
weeks later for measles total CF antibody on the pair.
(b) To diagnose past infection, send single sample for IgG
antibody.
Method : Anti-Measles IgM : Enzyme Immunoassay
Anti-Measles IgG : Immunofluorescence
Anti-Measles total : Complement Fixation Test
Test results : Acute infection : Acute serum positive for IgM
and/or paired sera showing ≥ 4
fold rise in CF Ab titres
Past infection/Immunity : Presence of IgG Ab in the
absence of specific IgM
Turnaround time : Anti-Measles IgM : 1 – 8 days
Anti-Measles IgG : 1 – 4 days
Anti-Measles Total : 1 – 6 days
Day(s) test set up : Anti-Measles IgM : Tuesday or Friday
Anti-Measles IgG : Tuesday and Friday
Anti-Measles Total : Tuesday and Thursday
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SECTION 4: SAMPLE COLLECTION & HANDLING – SPECIAL INSTRUCTIONS & LAB TESTS
MUMPS ANTIBODY
• Mumps IgM or IgG Antibody (anti-Mumps IgM or IgG)
• Mumps CF Total Antibody (anti-Mumps total)
Specimen required : 3 – 5 mL plain blood. Do not freeze.
(a) To diagnose acute infection, send single acute sample for
mumps IgM antibody and a second serum taken two
weeks later for mumps CF total antibody on the pair.
(b) To diagnose past infection, send single sample for
mumps IgG antibody.
Method : Anti-Mumps IgM or IgG : Immunofluorescence
Anti-Mumps total : Complement Fixation Test
Test results : Acute infection : Acute serum positive for IgM
Ab and/or paired sera showing
≥ 4 fold rise in CF Ab titres
Past infection/Immunity : Presence of IgG Ab in the
absence of specific IgM
Turnaround time : Anti-Mumps IgM or IgG : 1 – 4 days
Anti-Mumps Total : 1 – 6 days
Day(s) test set up : Anti-Mumps IgM or IgG : Tuesday and Friday
Anti-Mumps Total : Tuesday and Thursday
MYCOPLASMA PNEUMONIAE TOTAL ANTIBODY
Specimen required : 3 – 5 mL plain blood. Do not freeze.
Send an acute sample for total antibody. If the titre of the
first sample is <320, a second sample, to be sent two weeks
later, will be requested.
Method : Particle Agglutination
Test results : Acute infection : ≥ 4 fold rise of titre in paired sera. A
single sample having a titre of ≥ 320 is
suggestive of a recent infection.
Turnaround time : 1 – 4 days
Day(s) test set up : Monday, Wednesday and Friday
NEUROTROPIC VIRUS ANTIBODY PANEL
Total CF antibody against herpes simplex, measles, mumps and Japanese
encephalitis viruses are tested. Total CF antibody to varicella-zoster virus, although
not included in the panel, can also be requested.
Specimen required : 3 – 5 mL plain blood or 1 – 2 mL CSF. Do not freeze.
Send sera two weeks apart for rising titire.
For CSF, see Virology Section, General Guidelines for Virus
Serology.
Method : Complement Fixation Test
Test results : Paired sera showing ≥ 4 fold rise in titre or single samples
having titres of ≥ 128 to any of the tested viruses are
considered to have significant titres to that virus.
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VIROLOGY
Turnaround time : Single sample: 1 – 6 days
Paired sample: 1 – 6 days after receipt of second sample
Day(s) test set up : Tuesday and Thursday
NIPAH VIRUS IgG ANTIBODY
Specimen required : 3 – 5 mL plain (clotted) blood. Do not freeze.
(a) To diagnose acute infection, send blood two weeks apart.
(b) To diagnose past infection, send a single sample.
Method : Enzyme Immunoassay
Test results : Acute infection : Paired sera showing seroconversion
Past infection : Presence of IgG antibody in a single sample
Turnaround time : 2 – 30 days
Day(s) test set up : Once every month
PARVOVIRUS ANTIBODY
• Parvovirus B19 IgM Antibody
• Parvovirus B19 IgG Antibody
In acute Parvovirus B19 infection, both IgM and IgG tests are recommended
Specimen required : 3 – 5 mL plain blood. Do not freeze.
(a) To diagnose acute parvovirus infection, send acute
sample for IgM and IgG antibody, and a second sample
two weeks later for IgM and IgG.
(b) To diagnose past infection, send one sample for IgG
antibody.
Method : Enzyme Immunoassay
Test results : Acute infection : Presence of specific IgM
in acute serum and/or
convalescent serum and/or
seroconversion to IgG
Past infection/Immunity : Presence of IgG antibody in
the absence of specific IgM
Turnaround time : IgM or IgG : 1 – 8 days
Day(s) test set up : IgM or IgG : Thursday
RESPIRATORY VIRUS ANTIBODY
• Adenovirus CF Antibody
• Influenza Virus CF Antibody
• Parainfluenza Virus CF Antibody
• Respiratory Syncytial Virus CF Antibody
Specimen required : 3 mL plain blood for a single test. 6 – 8 mL for all tests
indicated above. Do not freeze.
To diagnose acute infection, send paired sera taken two
weeks apart. Send paired sera also for varicella-zoster virus
antibody and cytomegalovirus antibody if pneumonia is
suspected to be due to these viruses.
Method : Complement Fixation Test
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SECTION 4: SAMPLE COLLECTION & HANDLING – SPECIAL INSTRUCTIONS & LAB TESTS
Test results : Acute infection : Paired sera showing ≥ 4 fold rise in
antibody titre. A single sample having a
titre of ≥ 128 to any of the viruses tested
is suggestive of a recent acute infection.
Turnaround time : Single sample : 1 – 8 days
Paired sample : 1 – 8 days after receipt of second sample
Day(s) test set up : Thursday
RUBELLA ANTIBODY
• Rubella IgM Antibody (anti-Rubella IgM)
• Rubella IgG Antibody (anti-Rubella IgG)
• Rubella Total HI Antibody (anti-Rubella total)
Specimen required : 3 – 5 mL plain blood. Do not freeze.
(a) To diagnose acute rubella infection, send an acute serum
for rubella IgM antibody, and a second serum taken 7
– 10 days later for rubella total HI antibody on the pair.
(b) To evaluate a pregnant contact of a case of rubella, send first
sample immediately after exposure and second sample four
weeks after exposure for rubella total and IgM antibody.
(c) To determine the immunity status to rubella, send a
single sample for rubella IgG antibody.
Method : Anti-Rubella IgM : Enzyme Immunoassay
Anti-Rubella IgG : Microparticle Enzyme Immunoassay
Anti-Rubella total : Haemagglutination Inhibition
Test results : Acute infection: Rubella IgM antibody present and
confirmed by ≥ 4 fold rise of total Ab
titres in the paired sera.
Immunity status: Serum having rubella IgG antibody ≥ 15
IU/mL
Turnaround time : 1 – 8 days
Day(s) test set up : Anti-Rubella IgM : Wednesday
Anti-Rubella IgG : Thursday
Anti-Rubella total : Wednesday
SARS-CORONAVIRUS (SARS-COV) ANTIBODY
• SARS-CoV IgM (anti-SARS IgM)
• SARS-CoV IgG (anti-SARS IgG)
• SARS-CoV Total Antibody (anti-SARS total)
Specimen required : 6 – 8 mL plain blood in acute infection; 3 – 5 mL plain blood
to diagnose past infection. Do not freeze.
(a) To diagnose acute SARS, send acute sample for IgM
and total antibody, and a second sample two to three
weeks later for IgM, IgG and total antibody.
(b) To diagnose past infection, send one sample for IgG antibody.
Method : Anti-SARS IgM : Immunofluorescence
Anti-SARS IgG : Immunofluorescence
Anti-SARS total : Enzyme Immunoassay
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VIROLOGY
Test results : Acute infection : SARS IgM positive and confirmed by
≥ 4 fold rise of total Ab titres in the
paired sera or IgG seroconversion.
Past infection : SARS IgG positive
Turnaround time : Anti-SARS IgM or IgG : 1 – 4 days
Anti-SARS total (Positive report) : 3 – 7 days
Anti-SARS total (Negative report) : 1 – 4 days
Day(s) test set up : Anti-SARS IgM : Tuesday and Friday
Anti-SARS IgG : Tuesday and Friday
Anti-SARS total : Tuesday and Friday
VARICELLA-ZOSTER VIRUS (VZV) ANTIBODY
• VZV IgM Antibody (anti-VZV IgM)
• VZV IgG Antibody (anti-VZV IgG)
• VZV Total CF Antibody (anti-VZV total)
• VZV IgG Antibody (anti-VZV IgG ELFA)
Specimen required : 3 – 5 mL plain blood. Do not freeze.
(a) To diagnose acute varicella infection, send single acute
sample for VZV IgM antibody and a second serum taken
two weeks later for VZV total CF antibody on the pair.
(b) To diagnose past infection and immunity, send single
sample for VZV IgG antibody.
(c) For urgent screening for immunity, send sample for
VZV IgG antibody (ELFA).
Method : Anti-VZV IgM : Immunofluorescence
Anti-VZV IgG : Enzyme Immunoassay
Anti-VZV total : Complement Fixation Test
Anti-VZV IgG (ELFA) : Enzyme linked fluorescence assay
(for urgent testing)
Test results : Acute infection : Single sample positive for VZV IgM Ab
and/or paired sera showing ≥ 4 fold rise
in total CF Ab titres
Immunity : VZV IgG Ab present by EIA. Where
antibody levels are low, this will be
indicated on the report.
Turnaround time : Urgent cases:
Anti-VZV IgM : 3 – 4 hrs
Anti-VZV IgG (ELFA) : 1 – 2 hrs
Routine cases:
Anti-VZV IgM : 1 – 4 days
Anti-VZV IgG : 1 – 8 days
Anti-VZV total : 1 – 6 days after acute or second
sample
Day(s) test set up : Anti-VZV IgM/IgG (ELFA) : Stat for urgent cases
Anti-VZV IgM : Tuesday and Friday
Anti-VZV IgG : Tuesday
Anti-VZV total : Tuesday and Thursday
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SECTION 4: SAMPLE COLLECTION & HANDLING – SPECIAL INSTRUCTIONS & LAB TESTS
ALPHABETICAL TEST LISTING – ANTIGENS
CYTOMEGALOVIRUS ANTIGEN
Specimen required : 6 mL unclotted blood in EDTA bottle. Nasopharyngeal
aspirate, broncho-alveolar lavage, sputum, biopsy samples,
urine. Refrigerate samples except EDTA blood for CMV
pp65 Ag which should be kept at room temperature until
transport to laboratory. Do not freeze.
If virus isolation is required as well, send above samples
except blood and urine in VTM.
Otherwise, send all above except blood and urine in clean
bottles with 1 – 2 mL of sterile saline added. Send blood
and urine without VTM.
Method : Immunofluorescence
Test results : Reported as Negative or Positive
Turnaround time : 1 – 2 days
Day(s) test set up : Monday – Saturday
DENGUE VIRUS ANTIGEN
Specimen required : 3 – 5 mL plain blood, within 9 days of onset of illness
Method : Enzyme immunoassay
Test results : Report as positive or negative
Turnaround time : 1 – 4 days
Day(s) test set up : Tuesday and Friday
HERPES SIMPLEX VIRUS AND VARICELLA-ZOSTER VIRUS ANTIGEN
• Herpes Simplex Virus Antigen
• Varicella-Zoster Antigen
Sample Required : Fluid and scraping from vesicles on skin or mucosa
including conjunctivae and genitalia
Biopsy samples
Sputum, nasopharyngeal aspirate, bronchoalveolar lavage
If virus isolation is required as well, send all above in VTM.
Otherwise, send all above in clean bottles with 1 – 2 mL of
sterile saline added. Refrigerate samples until transport to
laboratory. Do not freeze.
Method : Immunofluorescence
Test results : Reported as Negative or Positive
Turnaround time : 1 – 2 days
Day(s) test set up : Monday – Saturday
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VIROLOGY
MEASLES AND MUMPS ANTIGEN
• Measles Antigen
• Mumps Antigen
Specimen required : Measles : Nasopharyngeal aspirate in 2 mL sterile saline
Mumps : Nasopharyngeal aspirate or saliva in 2 mL
sterile saline, CSF (1 – 2 mL, without saline) if
neurological symptoms present
Note : As direct antigen detection is less sensitive than isolation
for mumps, saliva should be sent in VTM so that isolation
can be carried out on the sample at the same time.
Refrigerate samples until transport to laboratory. Do not
freeze.
Method : Immunofluorescence
Test results : Reported as Negative or Positive
Turnaround time : 1 – 2 days
Day(s) test set up : Monday – Saturday
NOROVIRUS ANTIGEN
Specimen Required : 1 ml of liquid stool or cherry-size solid stool in a clean plain
screw-capped container, collected preferably within 3 days
of onset of illness
Method : Enzyme Immunoassay
Test results : Reported as Negative or Positive
Turnaround time : 1 – 7 days
Day(s) test set up : Tuesday
RESPIRATORY VIRUS ANTIGEN
Viruses tested : Respiratory syncytial virus, influenza A and B,
parainfluenza types 1 – 3, adenovirus
Specimen required : Sputum, nasopharyngeal aspirate, bronchoalveolar lavage
Lung biopsy or autopsy sample
If virus isolation is required as well, send all above in
VTM. Otherwise, send in clean bottles with 1 – 2 mL of
sterile saline added. Refrigerate samples until transport to
laboratory. Do not freeze.
Method : Immunofluorescence
Test results : Reported as Negative or Positive
Turnaround time : 1 – 2 days
Day(s) test set up : Monday – Saturday
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SECTION 4: SAMPLE COLLECTION & HANDLING – SPECIAL INSTRUCTIONS & LAB TESTS
ROTAVIRUS ANTIGEN
Specimen required : Stool (cherry size) in a clean screw-capped container. Do
not freeze.
Method : Chromatographic Immunoassay
Test results : Reported as Negative or Positive
Turnaround time : 1 day
Day(s) test set up : Monday – Saturday
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