Identifying HIV infection in South African women: How does a fourth generation HIV rapid test perform?

Abstract

BackgroundHIV rapid tests (RT) play an important role in tackling the HIV pandemic in South Africa. Third generation RT that detect HIV antibodies are currently used to diagnose HIV infection at the point of care. Determine Combo (DC) is the first fourth generation RT that detects both p24 antigen (p24Ag) and HIV antibodies (Ab), theoretically reducing the window period and increasing detection rates. Early detection of maternal HIV infection is important to mitigate the high risk of vertical transmission associated with acute maternal infection.ObjectivesWe assessed the performance of the DC RT against third generation RT in antenatal and post-partum women.MethodsThird generation RT Advance Quality and Acon were used in a serial algorithm to diagnose HIV infection in antenatal and post-partum women over six months at a tertiary hospital in Johannesburg, South Africa. This data provided the reference against which the DC RT was compared on plasma and whole blood samples.ResultsThe 1019 participants comprised 345 (34%) antenatal and 674 (66%) post-partum women. Ninety women (8.8%) tested HIV-positive of whom 59 (66%) were tested antenatally, and 31 (34%) post-partum yielding prevalence rates of 17.1% and 4.6% respectively. The sensitivity and specificity of the Ab component of DC on plasma antenatally was 100% (93.8% – 100%) and 100% (98.6% – 100%) respectively and post-partum was 100% (88.9% – 100%) and 99.6% (98.8% – 99.9%) respectively. One false positive and not a single true positive p24Ag was detected. Of 505 post-partum women who tested HIV-negative 6–12 months prior to enrolment, 12 (2.4%) seroconverted.ConclusionThe fourth generation DC offered no advantage over current third generation RT in the diagnosis of HIV infection.

Evaluation of a Rapid Point of Care Test for Detecting Acute and Established HIV Infection, and Examining the Role of Study Quality on Diagnostic Accuracy: A Bayesian Meta-Analysis

“…Multiple studies concluded that the performance of the Determine test was poor for detecting acute HIV, [ 31 , 36 – 39 , 44 , 46 ] and this meta-analysis provides evidence that the Determine Combo test, in its present form, is more suitable for use in testing/screening those populations which have already seroconverted. It should be noted that the accuracy of this test independent of the antibody component is only relevant for the period preceding seroconversion (the acute phase), when an antibody test would be negative.…”

“…Three studies (Patel et al, Laperche et al, and Bhowan et al) each contained more than one separate, unique evaluation of the Determine Combo test, and in these cases each evaluation was treated independently. [ 31 , 39 , 41 ] Individual study estimates with their confidence intervals are represented through forest plots as seen in Fig 2 . Raw data extracted from each individual study can be seen in S2 Table .…”

Evaluation of a 4th generation rapid HIV test for earlier and reliable detection of HIV infection in pregnancy

“…Other studies concur that the Combo RT offers no advantage over 3rd generation rapid tests in its lack of ability to detect acute HIV infections. 16 Perhaps the p24 antigen levels were lower at the baseline visit and the sensitivity of the antigen detection component of Combo RT is influenced by the timing of testing. One of the many challenges of detecting acute HIV infections is the very short "window period" and a mere assumption of the midpoint of seroconversion.…”

Poor Performance of the Determine HIV-1/2 Ag/Ab Combo Fourth-Generation Rapid Test for Detection of Acute Infections in a National Household Survey in Swaziland

“…The Determine HIV-1/2 Ag/Ab combo rapid test is the first such test that detects both Ag and Ab in two separate indicator lines. Early data on the performance of the Determine combo test to detect acute HIV infections in seroconversion panels suggested that it had a good performance in detecting early infections (19,20 (21)(22)(23)(24)(25)(26)(27)(28). Several of the studies were limited by small sample size and failure to follow up potential acute infections for seroconversion.…”