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Helen

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Helen Powered By Docstoc
					HIV Point Of Care Testing
        at GSTT
            Helen Dunn
  Operations Manager, Virology
  Infection and Immunology DU
        „Same-day‟ to POCT
• Virology approached by GUM early 2004
• They wished to replace same-day with
  POCT clinics in GUM.
• Also wished to set up POCT at a GP site
• Wished for advice and support from
  Virology
• Chosen test already in use at C&W GUM
             New approach
• Departure – first time non-laboratory staff
  had done serology test.
• Nurses and health advisers were to carry out
  test.
• Virology staff offered to train clinic staff.
• Virology staff asked to advise on testing
  facilities.
                Key aspects
•   1. Trust governance - ? Good for patient
•   2. Choice of test – only one CE-marked
•   3. Training
•   4. Quality – QC and QA
•   5. Multi-disciplinary
•   6. Audit
               1.Trust Governance
• Documentation: Operational policy, liaison between medical
  and laboratory team, cost benefit analysis.
• Conform to Trust POCT policy. Draft policy found.
  Pathology now has a POCT manager. Various programs within Trust.
• Advantages and disadvantages clear
   –   1 hour result instead of 2/3 days
   –   More expensive test but greater patient satisfaction.
   –   Less sensitive than lab-based assays for early infection
   –   Stress on clinic staff; rapid result. Proper training and support.
           2. Choice of test
• Abbott Determine already assessed at
  Chelsea & Westminster.
• Only test CE-marked at the time
                        3. Training
• Senior BMS and clinical scientist. Day and a half course.
• Tutorials – half day
   –   HIV, virus, disease and lab. diagnosis
   –   Principles of the Determine test
   –   Health and Safety; general and test
   –   Quality – QC and QA
• Practical instruction – full day
   –   How to use capillary
   –   How to interpret control
   –   SOPs, result sheets
   –   Testing panel of specimens
   –   Introduction to NEQAS
                     4. QC and QA
• QC
- procedural control in test
- Virology lab pre-tests new batches with controls supplied
  by HPA Standards Laboratory.
- SOPs for QC preparation and performance
- Two staff read results.
- Algorithm for repeat testing and confirmation
• QA
- participation in   external scheme.   ?NEQAS
   Both sites – GUM clinic and GP clinic
                   AUDIT
• Following 3 years of use in GUM clinic:-
• Adapted vertical audit, with clinic cooperation
• Concentrated on 3 areas:
1. Health and Safety
2. Performance of test
3. Clinic Procedures
Good result with performance and procedures. Only
   minor re-inforcing of safety measures required.
5. Multidisciplinary approach

         Virology advice,
              training                     GUM medic
        and confirmation.             and Trust Governance
  Consultant and senior scientists




                              Nurses
                        and Health Advisers-
                       named individual lead
                    2008
• 39 staff trained
• GUM clinic POCT still going strong.
• GP clinic folded 2007 – needs lots of local
  support.
• More community POCT clinics planned.
• Audit performed late 2007
                                2008
                         GUM Clinic    Community clinic


Start date           Oct 2004          Feb 2005


Individuals tested   1564              364


Positives            45(confirmed)     11 (confirmed)
                     1 false pos

HIV prevalence       2.9%              3.02%


NEQAS                All correct       All correct
           Findings of GP pilot study.
• One aim had been to encourage African
  residents to be tested.
• Study* found that the GP service was used
  significantly more by the Black ethnic
  community c.f. the GUM clinic:
  (16.5% v 8.7 % for same period).
• Fewer MSM at GP c.f. GUM (34.5% v
  41.3%)
•   *Surah et al. Paper submitted to STI
       HIV POCT QA update
• Worth doing if multiple sites take it up.
  THT may provide access to sites.
• ? small number of samples, more often
• ?small volumes
• ?spiked whole blood – how to preserve,
  inactivate, ship etc
            POCT and CPA
• What is the laboratory‟s role in POCT?
• Our Trust taking an ever greater interest.
• Full control of training, routine testing, QC
  and QA? Suitable accommodation?
  Accountable to CPA?
• Advisory role? Not responsible for service?
  CPA not involved?
                The Carter Report
   Review of NHS Pathology Services in England (2006)

Re: POCT
    “..fragmentation of parts of the service,
     particularly point-of-care services which are
     increasingly being undertaken by other
     members of the health care team, often with no
     reference to pathology services…”
                   The Carter Report
    Review of NHS Pathology Services in England (2006)

Recommendations
    (ix) the independent accreditation process is reviewed to
     ensure flexibility of approach and is extended to cover
     all providers of pathology services (including point-of
     care testing)..
    (x) all pathology providers, including point-of-care
     testing providers, are accredited in accordance with a
     national independent accreditation process….
    ..and which requires full participation in external quality
     assurance schemes..
Modernisation Initiative – evaluation
      of HIV rapid test kits
• Abbott Determine in
  regular use
          Two other tests:-

• INSTi
Rapidan Tester




                 blood
         Comparison of patients‟ samples
ABBOTT                     INSTI                     RAPIDAN

            Positive   Negative    fail   Positive   Negative   fail

106         106        0           0      102        1          3
HIV1        (100%)                        (96.2%)    (0.9%)     (2.8%)
positive

(whole
   blood)
100         0          100         0      0          100        0
negative               (100%)                        (100%)

(sera)
         Evaluation of 3 kits using QA/QC
   •
                                 material
        Results for NEQAS panel samples
           NEQAS                Nos        Abbott      INSTI       Rapidan
           HIV-1 positive       15         15 (100%)   11* (73%)   15 (100%)
           HIV-2 positive       1          1           0           0
           HIV negative         8          8 (100%)    8 (100%)    8 (100%)


                               *2 negative and 2 indeterminate
                               Only the Abbott assay detected the HIV-2 positive sample


         Results for 3 internal QC samples
              QC sample              Abbott            INSTI               Rapidan
              Negative               Neg               Neg                 Neg
              HIV-1 positive         Pos               Neg                 Pos (weak)
              HIV-2 positive         Pos               Neg                 Neg

HIV-2 positive sample not detected by INSTI and Rapidan.
INSTI failed to detect the HIV-1 positive and only a weak positive result was given with this sample by the Rapidan kit
Results for HIV-2 positive clinical samples


Sample        Nos       Abbott                INSTI                    Rapidan

HIV-1/HIV-2   1         1                     1                        1

HIV-2         4         4                     4*                       4**


              *2 results were very weak, ** 3 results were very weak
     Evaluation in community
- Several THT clinics each using the
   Determine. 100 tests at each site.
- Both will run the INSTi and the RAPIDAN
   in parallel with the Determine.
 - A „real-life‟evaluation of those assays in
   comparison with Determine: ease of use,
   safe handling, interpretation.
            Chlamydia POCT
• Tests are available on the internet for self-
  testing – all test for antigen. E.g 15 mins
• Testing services available on internet – e.g.
  THT – pack sent to patient who takes own
  specimen and sends for testing. – 2 days
• Gold standard now NAAT.
• Some tests are for „own use‟, some for
  „professional use‟ only.
      Sensitivity vs. accessibility
• Debate about choosing less-sensitive over tech.-demanding
  test to avert STIs.
• Vickerman et al. estimate required sensitivity at only 50%
  if either 55% fail to return for treatment and there is no
  transmission, or 80% return and 50% infect partner during
  delay.(STI 2003)
• One rapid Ag test claims sensitivity of 81% c.f. SDA and
  83% c.f. PCR. (BMJ 2007).
            Final comments
• > 3-year experience of HIV POCT.
• Clinic / laboratory collaboration essential
• QA material for POCT needed.
• Lab evaluation of other kits gives concern
• Community-based evaluation will be
  valuable.
• Desire for other infectious disease POCT.
                      Colleagues
•   Virology, GSTT             • Genitourinary medicine,
•   Dr. S. O‟Shea                GSTT
•   Dr. W. Tong                • Dr. Emma Fox
•   Ms. K. Ashworth            • Dr. Cindy Sethi
•   Ms. S. Sliney              • Ms. Chikami Shimada
•   Ms. J. Stone               • Ms. Rebecca Bickersteth
                               • Mr. Dilip Lakhani
•   Lambeth Walk GP
•   Ms. Christina Fitzgerald   • Modernisation Initiative
•   Ms. Maria Walker           • Keith Marshall
•   Ms. Andrea Scott

				
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posted:9/9/2011
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