Dried blood spot specimens are a suitable alternative sample type for HIV-1 viral load measurement and drug resistance genotyping in patients receiving first-line antiretroviral therapy.

BACKGROUND: Antiretroviral therapy (ART) is being administered in developing nations at unprecedented numbers following the World Health Organization's (WHO) development of standardized first-line drug regimens. To ensure continued efficacy of these drug regimens, WHO recommends monitoring virological responses and development of human immunodeficiency virus (HIV) drug resistance (HIVDR) in HIV-infected patients in a prospective cohort. The current study compared dried fluid spot specimens with the reference standard plasma specimens as a practical tool for viral load (VL) and HIVDR genotyping in resource-limited settings.
METHODS: Dried blood spot (DBS), dried plasma spot (DPS), and plasma specimens were collected from 173 -patients receiving ART at 2 hospital sites in Abuja, Nigeria. HIV-1 VL analysis was performed using NucliSENS EasyQ HIV-1 v1.1 RUO test kits. Genotyping of the HIV-1 pol gene was performed using a broadly sensitive in-house assay.
RESULTS: Direct comparison of VL levels showed that DBS specimens, and not DPS specimens, gave results comparable to those of plasma specimens (P = .0619 and .0007, respectively); however, both DBS and DPS specimens had excellent correlation with plasma specimens in predicting virological failure (VL, ≥1000 copies/mL) in patients (κ = 0.78 and 0.83, respectively). Of the 18 specimens with a plasma VL ≥1000 copies/mL, HIVDR genotyping rates were 100% in DBS and 38.9% in DPS specimens, and DBS specimens identified 61 of 65 HIVDR mutations (93.8%) identified in plasma specimens.
CONCLUSIONS: Our results indicate that DBS specimens could be used for surveys to monitor HIVDR prevention failure in resource-limited settings.