Comparison of Ahlstrom Grade 226, Munktell TFN, and Whatman 903 filter papers for Dried Blood Spot (DBS) specimen collection and subsequent HIV-1 viral load and drug-resistance genotyping analysis.

Rottinghaus E, Bile E, Modukanele M, Maruping M, Mine M, Nkengasong J, Yang C.

Source

International Laboratory Branch, Division of Global HIV/AIDS, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA.

Abstract

Background: Dried blood spots (DBS) collected on filter paper have eased the difficulty of blood collection in resource-limited settings. Currently Whatman 903 (W-903) is the only filter paper that has been used for HIV viral load (VL) and HIV drug resistance (HIVDR) testing. We therefore evaluated two additional commercially available filter papers, Ahlstrom grade 226 (A-226) and Munktell TFN (M-TFN) for VL and HIVDR genotyping using W-903 as a comparison group.Methods: DBS specimens were generated from 344 adult ART-patients in Botswana. VL was measured with NucliSENS EasyQ HIV-1 v2.0 and genotyping was performed for those specimens with a detectable VL (≥ 2.90 log10 copies/ml) using an in-house method.Results: Bland-Altman analysis revealed strong concordance in quantitative VL analysis between W-903 and A-226 (bias= -0.034 ± 0.246 log10 copies/ml [Mean difference ± SD]) and M-TFN (bias = -0.028± 0.186 log10 copies/ml) while qualitative VL analysis for virological failure determination, defined as VL ≥ 3.00 log10 copies/ml, showed low sensitivities for A-266 (71.54%) and M-TFN (65.71%) when compared to W-903. DBS collected on M-TFN had the highest genotyping efficiency (100%) compared to W-903 and A-226 (91.7%), and appear more sensitive in detecting major HIVDR mutations.Conclusions: DBS collected on A-226 and M-TFN filter papers performed similarly to W-903 for quantitative VL analysis and HIVDR detection. Together, the encouraging genotyping results and the variability observed in determining virological failure from this small pilot study warrant further investigation of A-226 and M-TFN as specimen collection devices for HIVDR monitoring surveys.