Stability of dried blood spots for HIV-1 drug resistance analysis.

The wide scale application of dried blood spots (DBS) as a collection tool for low-cost HIV drug resistance testing requires a greater understanding of the accuracy of DBS for genotype analysis and the stability of DBS under various environmental conditions. Analysis of a 50microl DBS via a single amplicon, nested PCR-based in-house assay (the Burnet genotyping assay) showed an average nucleotide concordance of 98.9% with plasma samples, although only 65% of nucleotide mixtures detected in plasma were also detected within DBS.

Evaluation of the blood stabilizers TransFix and Cyto-Chex BCT for low-cost CD4 T-cell methodologies.

TransFix(TM) and Cyto-Chex((R)) BCT (blood collection tube) reagents have been shown to maintain whole blood integrity for delayed immunophenotyping by flow cytometry. We evaluated the ability of these blood-stabilizing reagents to preserve HIV-seropositive blood for delayed CD4(+) T-cell quantification utilizing the Dynal((R)) Biotech T4 Quant Kit. TransFix was added to EDTA-anticoagulated whole blood and tested at a 1:10 dilution over 7 d using the Dynal (n = 21) manual method.

Evaluation of the Cavidi ExaVir Load assay (version 3) for plasma human immunodeficiency virus type 1 load monitoring.

We evaluated the new low-cost ExaVir Load (version 3) reverse transcriptase viral load assay against the Roche Cobas Amplicor assay. Results for samples tested using the reverse transcriptase assay correlated well with those obtained with the Roche assay (r = 0.85; n = 202).