High cost of Xpert MTB/RIF ® testing per tuberculosis case diagnosed at
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Transcript of High cost of Xpert MTB/RIF ® testing per tuberculosis case diagnosed at
High cost of Xpert MTB/RIF® testing per
tuberculosis case diagnosed atPartners in Hope Medical Center,
a publicprivate 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. Pfaff1,21Partners in Hope, Lilongwe, Malawi, 2University of California, Los Angeles, Program in Global Health, Los Angeles, United States
EQUIP-MALAWI
Background - Malawi
Population 15 millionHIV prevalence 12-
15%TB prevalence
219/100 000TB patients HIV
Positive - 63%Per capita health
expenditure $50
Partners in Hope Medical CenterPublic private clinic
- 4300 HIV patients.
TB diagnosis and treatment centerAFB microscopyCulture not
routinely available
Introduction of Xpert MTB/RIF® Xpert machine donated Aug 2011Donation 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 smearsXpert testing - morning samples AFB smears – mixed
ObjectivesDescribe 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)
MethodsRetrospective review of the
AFB laboratory recordsclinical data not collected only included sputum samples
Methods – smear definitionsSamples - 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 ResultsPatients
417
(+) by Xpert61
(14.6%)
58 had smear results
No sputum was (+) smear and (-) Xpert
Xpert and sputum results58 positive Xpert that had smear results
35 AFB (+)60%
15 AFB scanty26%
8 AFB (-)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 analysisOnly based on the price of the
cartridgeDid not include the cost of the
machine, maintenance, lab staff etc.
Cost using Xpert following AFB smear
Total smear (-) patients
Smear (-) patients with (+) Xpert
Number smear (-) patients tested by Xpert to detect one case
Cost per test cartridge
Cost to detect one smear negative case
Scanty smears considered positive
367 8 46 $20 $920
Scanty smears considered negative
382 23 16 $20 $320
ConclusionsIncreased yield over microscopy
alone by 16 % -65% Depends on quality of smear microscopy and
guidelinesCost 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 studyRetrospectiveCulture was not done to confirm (-)
Xpert tests AFB reader was not always blinded
to Xpert result increase number of scanty reads?
Mixed patient populationSome newly diagnosed ART naive,
some already on ART
AcknowledgementsStaff and patients at Partners in HopeLisa HirschhornRisa HoffmanSupport from PEPFAR/USAID Malawi for
clinical operations at Partners in HopeAfrica Mission Health Care Foundation