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PIH Experience with Gene Expert 2011 Presentation to NTP

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					   High cost of Xpert MTB/RIF testing per                    ®



        tuberculosis case diagnosed at
  Partners in Hope Medical Center, a public
     private HIV care clinic in Lilongwe,
                   Malawi.
   Comparison with fluorescence microscopy in a well-
   equipped and experienced real world AFB laboratory

 D. Fitzgerald1,2, P. Jansen1, C. Chipungu1, V. Dindi1, J. Fielder1, C.
   Pfaff1,2
   1Partners in Hope, Lilongwe, Malawi, 2University of California, Los Angeles, Program
   in Global Health, Los Angeles, United States

EQUIP-MALAWI
Background - Malawi

 Population 15 million
 HIV prevalence 12-15%
 TB prevalence 219/100 000
 TB patients HIV Positive - 63%
 Per capita health expenditure
  $50
Partners in Hope Medical Center
 Public private clinic - 4300
  HIV patients.
 TB diagnosis and treatment
  center
    AFB microscopy
    Culture not routinely
     available
Introduction of Xpert MTB/RIF                ®


Xpert machine donated Aug 2011
Donation of “near expiration date” cartridges -
 ability to increase testing of TB suspects
Introduction of Xpert MTB/RIF                     ®


 Population: All HIV(+) patients seen at Partners
  in Hope who were identified as TB suspects
    Suspicion of possibility TB by experienced clinician
     based on history and examination
 Lab: 1 Xpert test and 2 AFB smears
     Xpert testing - morning samples
     AFB smears – mixed
Objectives
Describe in somewhat ideal real-world setting how
  to best use Xpert to improve TB case finding
 Percent of smear (-) sputum samples with (+)
  Xpert
 Number of smear (-) sputum samples that need
  to be tested to yield one (+) Xpert
 Cost of Xpert testing per smear (-) case detected
  (using AFB smear as initial test per Malawi draft
  Xpert guidelines)
Methods
 Retrospective review of the AFB
  laboratory records
  clinical data not collected
  only included sputum samples
Methods – smear definitions
 Samples - positive, negative or scanty (<10
  AFB/100 HPF)
 2007 guidelines – single scanty considered (-)
 2012 guidelines – single scanty considered (+)
 Analysis was done both with single scanty
  considered (+) and single scanty considered (-)
    Xpert Results
            Patients
              417


          (+) by Xpert
               61
            (14.6%)

         58 had smear
            results



No sputum was (+) smear and (-) Xpert
Xpert and sputum results
         58 positive Xpert that had smear results



  35 AFB (+)      15 AFB scanty       8 AFB (-)
     60%              26%               14%

                                      Increased detection by 16%



                       Increased detection rate by 65%
                            if scanty considered (-)
Numbers of patients needed to be tested
with Xpert to detect one case of TB

  Using protocol of AFB smear first and Xpert
   if smear “(-)”
  If scanty considered (-) – 16 patients
  If scanty considered (+) – 46 patients

  If Xpert was done on all cases, need to test
   8 patients to detect one case
Cost analysis
 Only based on the price of the cartridge
 Did not include the cost of the machine,
  maintenance, lab staff etc.
     Cost using Xpert following AFB smear
                Total smear    Smear (-)   Number      Cost per    Cost to
                (-) patients   patients    smear (-)   test        detect
                               with (+)    patients    cartridge   one smear
                               Xpert       tested by               negative
                                           Xpert to                case
                                           detect
                                           one case
Scanty smears       367            8          46         $20        $920
considered
positive
Scanty smears       382           23          16         $20        $320
considered
negative
Conclusions
 Increased yield over microscopy alone by 16 % -
  65%
  Depends on quality of smear microscopy and guidelines
 Cost per extra case if using smear as initial screen
  was quite high ($320-$920)
 Only possible to replace smear microscopy if
  costs come down
Caveats of study
 Retrospective
 Culture was not done to confirm (-) Xpert tests
 AFB reader was not always blinded to Xpert
  result
  increase number of scanty reads?
 Mixed patient population
  Some newly diagnosed ART naive, some already on
   ART
Acknowledgements
 Staff and patients at Partners in Hope
 Lisa Hirschhorn
 Risa Hoffman
 Support from PEPFAR/USAID Malawi for clinical
  operations at Partners in Hope
 Africa Mission Health Care Foundation

				
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posted:7/25/2013
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