A decision-making process to guide the potential application of a hepatitis A virus and parvovirus B19 nucleic acid test for qualifying plasma for fractionation.

BACKGROUND

The Roche cobas DPX assay (Roche Diagnostics) is a nucleic acid test (NAT) that detects parvovirus B19 (B19V) and hepatitis A virus (HAV) and enhances the safety of fractionated plasma protein products. Implementation of this NAT requires multiple decisions focused on test characteristics, test operationalization, and result interpretation. This study uses a decision-making process to guide the potential application of this NAT to qualify plasma for fractionation.

METHODS

A basic decision tree approach was used to undertake a stepwise feasibility study of the B19V/HAV assay in a blood donor setting. Limit of detection, reproducibility, and pooling studies utilized mocked-up B19V (genotypes 1 and 2) and HAV (genotypes 1a, 2a, and 3a) specimens (BioQControl; Biologicals Quality Control B.V.), Somagen (LGC SERACARE), and anonymized COVID-19 convalescent plasma (CCP; Canadian Blood Services). The Hamilton Microlab STAR IVD Pipettor generated HAV and B19V specimen pools of 96, 24, and 6. Pools and individual specimens were tested using the DPX (Duplex HAV and Parvovirus B19 Nucleic Acid Test) on the cobas 6800/8800 System. Data were collated using Excel (Microsoft, Seattle, WA, USA).

RESULTS

The Roche cobas DPX reproducibly detected dilutions of B19V and HAV. Pools of 24 and 6 reproducibly detected B19V at acceptable Ct values; pools of 6 reproducibly detected HAV, although at later Ct values.

CONCLUSIONS

Using a simple decision tree approach, this study describes how a B19V and HAV NAT could be applied for the qualification of plasma for fractionation.