Performance and logistical challenges of alternative HIV-1 virological monitoring options in a clinical setting of Harare, Zimbabwe

Biomed Res Int. 2014:2014:102598. doi: 10.1155/2014/102598. Epub 2014 Jun 15.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Dried Blood Spot Testing
  • HIV Core Protein p24 / isolation & purification*
  • HIV Infections / blood*
  • HIV Infections / virology
  • HIV-1 / isolation & purification*
  • Humans
  • Reagent Kits, Diagnostic
  • Specimen Handling
  • Viral Load
  • Virology / methods*
  • Zimbabwe


  • HIV Core Protein p24
  • Reagent Kits, Diagnostic