Stability of HIV-1 Nucleic Acids in cobas Plasma Separation Card for Viral Load Measurement

OBJECTIVES: Our study aimed to evaluate the stability of human immunodeficiency virus 1 (HIV-1) RNA on cobas plasma separation card (PSC) specimens for viral load (VL) testing after being exposed to varied temperatures and storage times. METHODS: For this purpose, venous PSC specimens were collected and stored at 25ºC to 42ºC for a period of up to 28 days. Plasma VL at baseline was used as reference, against which PSC VL was compared at different time points. RESULTS: From the 30 patients included in the study, 600 PSC and 30 fresh plasma specimens were obtained. Plasma VL at baseline was fewer than 1,000 copies/mL in 16 patients, and 99.4% of PSCs from these patients yielded nonquantifiable VL at all temperature ranges and time points. During the study period, minor variation of VL was observed in PSCs obtained from 13 patients with plasma VL fewer than 1,000 copies/mL at baseline. For the patient with plasma VL at 1,000 copies/mL, the PSC VL varied from undetectable to 1,670 copies/mL. CONCLUSIONS: Our results show minor variation of VL in PSC specimens in the study conditions. HIV RNA is stable in PSCs exposed to high temperatures for up to 28 days.