Performance and Logistical Challenges of Alternative HIV-1 Virological Monitoring Options in a Clinical Setting of Harare, Zimbabwe

Abstract

We evaluated a low-cost virological failure assay (VFA) on plasma and dried blood spot (DBS) specimens from HIV-1 infected patients attending an HIV clinic in Harare. The results were compared to the performance of the ultrasensitive heat-denatured p24 assay (p24). The COBAS AmpliPrep/COBAS TaqMan HIV-1 test, version 2.0, served as the gold standard. Using a cutoff of 5,000 copies/mL, the plasma VFA had a sensitivity of 94.5% and specificity of 92.7% and was largely superior to the VFA on DBS (sensitivity = 61.9%; specificity = 99.0%) or to the p24 (sensitivity = 54.3%; specificity = 82.3%) when tested on 302 HIV treated and untreated patients. However, among the 202 long-term ART-exposed patients, the sensitivity of the VFA decreased to 72.7% and to 35.7% using a threshold of 5,000 and 1,000 RNA copies/mL, respectively. We show that the VFA (either on plasma or on DBS) and the p24 are not reliable to monitor long-term treated, HIV-1 infected patients. Moreover, achieving acceptable assay sensitivity using DBS proved technically difficult in a less-experienced laboratory. Importantly, the high level of virological suppression (93%) indicated that quality care focused on treatment adherence limits virological failure even when PCR-based viral load monitoring is not available.

Diagnosis of Human Immunodeficiency Virus Infection

“…One key factor that can limit access to VL testing is the high cost for testing. VL testing costs range from US$30 to US$125 per test (195,196), and more than half of the cost can be attributed to the cost of regents and consumables (197). To increase access to VL testing and improve patient management, the Roche Global Access Program significantly reduced the price of VL testing reagents for low-and middle-income countries in 2014 (198).…”

Point-of-Care Cepheid Xpert HIV-1 Viral Load Test in Rural African Communities Is Feasible and Reliable

“…In resourcelimited settings, especially in rural areas, laboratory-based HIV-1 RNA testing remains challenging for many reasons, among them insufficient access to laboratory facilities, cold-chain management shortcomings, and inability to consistently provide for sample transportation (8)(9)(10). Delays in the reporting of results may also negatively impact the HIV treatment cascade (11)(12)(13).…”

Use of a Chagas Urine Nanoparticle Test (Chunap) to Correlate with Parasitemia Levels in T. cruzi/HIV Co-infected Patients

“…Mean age was 36.8 years (SD: 15.1 years). Mean levels of HIV loads were considerably higher (187387.5 copies/ml, SD: 549436.2 copies/ml) [ 27 , 28 ], which could be explained by the short duration of HIV diagnosis (mean: 28.3 months, SD: 24.9 months). Mean levels of CD4+ cell and CD8+ cell counts were within normal limits according to the CDC classification (301.3 cells, SD: 226.2 cells, and 765.9 cells, SD: 543.4 cells, respectively) [ 29 ].…”

“…As a result, high viral loads were observed in patients with and without Chagas disease (mean: 220969.5 and 84960.6 copy number/ml blood, respectively). We therefore used a classification of high HIV load as follows: 1) <5000 copies/ml, 2) ≥5000–30 000 copies/ml, and 3) >30 000 copies/ml [ 27 , 28 ]. The immunosuppression status was determined by the levels of CD4+ T-cell counts according to CDC classification system as follow: 1) ≤ 200, 2) 201–500 and 3) ≥ 500 [ 29 ].…”