Sensitivity and specificity of dried blood spots for HIV-1 viral load quantification: A laboratory assessment of 3 commercial assays

• Published in: Medicine (Baltimore) 2016-11, Vol.95 (48), p.e5475-e5475
• Main Authors: Pannus, Pieter, Claus, Maarten, Gonzalez, Maria Mercedes Perez, Ford, Nathan, Fransen, Katrien
• Format: Article
• Language: English
• Subjects: Blood - virology; Diagnostic Accuracy Study; HIV-1; Humans; Molecular Diagnostic Techniques; Reagent Kits, Diagnostic; Sensitivity and Specificity; Specimen Handling - methods; Viral Load
• ISSN: 0025-7974; 1536-5964
• DOI: 10.1097/MD.0000000000005475

The use of dried blood spots (DBS) instead of plasma as a specimen type for HIV-1 viral load (VL) testing facilitates the decentralization of specimen collection and can increase access to VL testing in resource-limited settings. The performance of DBS for VL testing is lower, however, when compared to the gold standard sample type plasma. In this diagnostic accuracy study, we evaluated 3 VL assays with DBS.Participants were recruited between August 2012 and April 2015. Both plasma and DBS specimens were prepared and tested for HIV-1 VL with the Roche CAP/CTM HIV-1 test v2.0, the Abbott RealTime HIV-1, and the bioMérieux NucliSENS EasyQ HIV-1 v2.0. Sensitivity and specificity to detect treatment failure at a threshold of 1000 cps/mL with DBS were determined.A total of 272 HIV-positive patients and 51 HIV-negative people were recruited in the study. The mean difference or bias between plasma and DBS VL was 25% of the specimens differed by >0.5 log cps/mL.All 3 assays had comparable sensitivities around 80% and specificities around 90%. Upward misclassification rates were around 10%, but downward misclassification rates ranged from 20.3% to 23.6%. Differences in between assays were not statistically significant (P > 0.1).The 3 VL assays evaluated had suboptimal performance with DBS but still performed better than immunological or clinical monitoring. Even after the introduction of the much-anticipated point-of-care VL devices, it is expected that DBS will remain important as a complementary option for supporting access to VL monitoring, particularly in rural, resource-limited settings. Manufacturers should accelerate efforts to develop more reliable, sensitive and specific methods to test VL on DBS specimens.