Performance of plasma separation cards for HIV drug-resistance genotyping in a resource-limited setting: comparison with plasma samples.

BACKGROUND

HIV drug resistance (HIVDR) threatens the effectiveness of antiretroviral therapy (ART) programmes in low- and middle-income countries. The Cobas Plasma Separation Card (PSC) is a recently developed specimen collection tool with potential to expand access to HIVDR genotyping in remote settings. This study evaluates PSC performance for HIVDR genotyping compared with plasma.

METHODS

Paired plasma and PSC specimens were selected from 250 people living with HIV (PLHIV) on ART ≥6 months with viral load (VL) ≥1000 copies/mL. HIVDR genotyping followed CDC Atlanta in-house protocol; resistance interpretation used the Stanford HIVdb algorithm. Paired sequences were compared for subtype, nucleotide similarity, mutation profile and drug-resistance classification.

RESULTS

Twenty paired specimens met inclusion criteria. Amplification of the HIV-1 Pol gene succeeded in 19/20 (95%) PSC samples. Of 19 paired sequences, nucleotide similarity was 98.5% (IQR 98.0%-99.3%). Eleven plasma samples showed 37 major drug-resistance mutations (MDM); 35 (94.6%) concordant MDM were identified in PSC. Discordances in four pairs were limited to mixed versus single bases and did not alter drug-resistance classification. Only one pair showed a clinically significant discordance (K103N detected in plasma but not initially in PSC).

CONCLUSIONS

PSC demonstrated good concordance with plasma for HIVDR genotyping and has potential as an alternative specimen type for clinical practice and surveillance in resource-limited settings.