Sensitivity And Specificity Of Hiv Rapid Tests Used For Research And Voluntary Counselling And Testing

Abstract

Background: HIV rapid tests (RT) are a quick and non-technically demanding means to perform HIV voluntary counselling and testing (VCT) but understanding their limitations is vital to delivering quality VCT. Objective: To determine the sensitivity and specificity of HIV rapid tests used for research and voluntary counselling and testing at four sites in East Africa. Design: Cross-sectional study. Setting: Masaka District, Uganda; a sugar plantation in Kakira, Uganda; Coastal Villages in the Kilifi District of Kenya; and the Urban slum of Kangemi located West of Nairobi, Kenya. Subjects: Six thousands two hundred and fifty five consenting volunteers were enrolled into the study, and 675 prevalent HIV infections were identified. Results: The RT sensitivity tended to be high for all assays at all sites (97.63-100%) with the exception of the Uni-Gold assay (90.24% in Kangemi, 96.58% in Kilifi). Twenty four RT results were recorded as 'weak positives', 22 (92%) of which were negative by ELISA. There was a high rate of RT false positives in Uganda (positive predictive values ranging from 45.70% to 86.62%). Conclusions: The sensitivity and specificity of the RT varied significantly across sites. The rate of RT misclassification in Uganda suggests that a multiple test algorithm may be preferable to a single test as screener for HIV VCT.

Towards more accurate HIV testing in sub‐Saharan Africa: a multi‐site evaluation of HIV RDTs and risk factors for false positives

“…It has been postulated that weak reactive test lines/dots are more likely to be false positive than true positive results and that considering them as potentially negative might reduce false-positive results [2,10,15,18,19,28,29]. We detected weak testing lines only with SD Bioline and First Response, the latter showing weak results on almost 50% of reactive tests for HIV-2.…”

“…The latest WHO evaluations of single HIV RDTs reported highly sensitive and specific results, with most tests exceeding the recommended thresholds for performance [6,7]. However, the results of studies of RDT accuracy at laboratory and field level are more varied than they are for HIV testing algorithms [8][9][10][11][12][13][14][15][16][17][18][19].…”

HIV misdiagnosis in sub‐Saharan Africa: performance of diagnostic algorithms at six testing sites

“…Reports of unacceptably high error rates in RDT-based HIV testing in some resource-constrained settings [5][6][7][8][9][10][11][12][13][14][15][16][17] led us to conduct a large, multisite study to assess the performance of testing algorithms used at six sites in sub-Saharan Africa. The results of the HIV testing algorithms routinely used in these sites were compared to those of an internationally recognized reference algorithm from the AIDS reference laboratory for HIV at ITM, Antwerp.…”

“…Furthermore, the WHO recommends using serological assays/RDTs with a sensitivity of at least 99%; the first RDT should have a specificity of at least 98%, while the second and third RDTs should have a specificity of at least 99%. Despite the good performance of numerous individual RDTs in recent WHO evaluations [2,3], false-positive results have been reported from projects operated by Médecins sans Frontières (MSF) [5][6][7], a humanitarian emergency organization, and by other actors [7][8][9][10][11][12][13][14][15][16][17]. A false-positive result is likely to be psychologically traumatic to the patient and may trigger inappropriate, potentially harmful treatment [6].…”

Linkage to HIV care before and after the introduction of provider-initiated testing and counselling in six Rwandan health facilities

“…Some patients reported an HIV-negative test after their initial positive test when they were tested at a different facility. False positive rapid-test results have been reported in the literature (Anzala et al, 2008;Gray et al, 2007;Kagulire et al, 2011;Klarkowski et al, 2009), but operational issues, such as non-observance of standard operating procedures and lack of quality control, might also play a role (Shanks, Klarkowski, & O'Brien, 2013).…”