Nucleic acid testing of donor plasma minipools (MPs) indicates that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNAemia is infrequent, according to a study published online May 27 in Transfusion.

Sonia Bakkour, Ph.D., from the Vitalant Research Institute in San Francisco, and colleagues tested collected from March 7 to Sept. 25, 2020, for SARS-CoV-2 RNA (vRNA) in donor plasma MPs of six or 16 donations. To estimate , reactive MPs were tested by transcription-mediated amplification after serial dilution.

Overall, 17,995 MPs corresponding to about 258,000 donations were tested for vRNA. The researchers identified three confirmed reactive MP16s, for an estimated prevalence of 1.16/100,000 vRNA reactive donations. The vRNA-reactive samples were not reactive for antibody; within each MP, the estimated viral loads of the (presumed single) positive donations ranged from <1,000 to <4,000 copies/mL. No infectivity was seen in inoculated permissive cell cultures when tested.

"Other studies have shown that in rare cases where a blood sample tested positive, transmission by blood transfusion has not occurred," Bakkour said in a statement. "Therefore, it appears safe to receive blood as a transfusion recipient and to keep donating blood, without fear of transmitting COVID-19 as long as current screenings are used."

Two authors disclosed ties to Grifols Diagnostic Solutions.