An assessment of the use of viral load as a marker for Cryptococcal Antigen screening among HIV positive patients at Jaramogi Oginga Odinga Teaching and Referral Hospital

Burmen Barbara

Abstract


Cryptococcal meningitis, one of the leading
opportunistic infections among HIV-infected persons with
advanced disease, has a mortality rate of 67%. Cryptococcal
Antigen (CrAg) test detects Cryptococcus neoformans antigen
threeweeks before onset of symptoms when institution of therapy
is likely to improve patient outcomes. Previously, CD4counts
were used for ART monitoring and patients were only flagged
for a targeted viral load test (VL) to confirm suspected treatment
failure if there was a 30% CD4 decline from peak or failure to
increase CD4 counts to 100 cells/µl after 12 months of therapy.
At that time, patients were eligible for CrAg screening when
CD4 counts were <100 cells/µl. Currently bi-annual HIV viral
load measurements (VL) are used in ART monitoring and a
patient is said to be failing therapy if two consecutive VL counts
are ≥1000 copies/ml with institution of adherence and
opportunistic infection treatment interventions between the two
VL tests; CD4 tests are still be used in the differential diagnosis
of some Opportunistic infections in symptomatic HIV-infected
patients. A cross-sectional survey, riding on routine HIV
program work, will be done to determine the prevalence of
cryptococcalantigenemia and to assess the usability of VL as a
marker for cryptococcal antigen testing in HIV-infected patients.
We will perform CD4 quantification and CrAg test on blood
samples for routine VL drawn from HIV infected patients at the
JOOTRH HIV clinic. Laboratory results from these tests (CD4,
CrAg, and VL) will be linked to the patients’ medical records at
the HIV clinic. Among patients who test CrAg positive,
measures of validity will be computed for CD4 criteria against
VL defined criteria. Subsequently, we will determine whether
VL measurements can be used as an alternative to CD4
measurements. Then VL can then be used to direct when to
screen for C. neoformans.

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