From Pathogen to Infectious Disease Diagnosis: cobas MPX-E adds HEV to NAT screening

This is the latest episode of our From Pathogen to Infectious Disease Diagnosis podcast, where we discuss the relationship between clinicians and laboratory professionals and detail the latest in diagnostics.

Transfusion safety increasingly depends on consolidating viral nucleic acid testing (NAT) into fewer, faster steps. A newly available multiplex assay now screens donated blood for four bloodborne viruses in a single reaction, folding hepatitis E into the same workflow as HIV and hepatitis B (HBV) and C (HCV).

On a recent episode of From Pathogen to Infectious Disease Diagnosis, host Rodney Rohde, PhD, spoke with Nico Michel, PhD, lifecycle leader, Roche Diagnostics International. Michel leads global lifecycle management for the company's molecular infectious disease and donor screening portfolio. Their discussion centered on the cobas MPX-E assay and the operational strain facing blood screening laboratories.

Blood supply crises recur with little warning. Germany's inventory recently fell to 1.5 days, and the American Red Cross reported a 35% single-month decline in January after a severe storm. Red cells must be transfused within 42 days and platelets within 5 to 7 days, so any drop in donations places immediate pressure on laboratories, according to Michel.

“Blood supply crisis keep happening…with reserves typically low and often affected them by seasonal factors like weather disruptions. There's also cold and flu seasons that have an impact, but sometimes holiday periods and summer travel off of donors. So any kind of reduction in donation rates then immediately creates real pressure on such a system,” Michel said.

The cobas MPX-E assay uses multiplex real-time polymerase chain reaction (PCR) to detect and discriminate HIV, HCV, HBV, and hepatitis E (HEV) in distinct channels. Earlier workflows often required separate screening assays plus sequential discriminatory testing to identify a reactive target, adding steps and delay. Consolidating detection and discrimination into one test shortens turnaround from donation to release and lets laboratories process more donations on existing instruments.

HEV accounts for an estimated 20 million infections and 70,000 deaths worldwide each year, and most carriers remain asymptomatic, leaving routine screening as the main safeguard for immunocompromised transfusion recipients. Historically, the labor and cost of standalone HEV testing limited adoption, a barrier the multiplex format lowers by adding the target without new instrumentation.

“We're seeing a lot of momentum towards universal HEV screening as a better or standard access, and of course, I mean, with multiplex PCR approaches like our cobas MPX-E, this exemplifies the shift and makes the adoption of HEV nucleic acid testing,” Michel said.

The assay also applies dual-target detection across two conserved regions of the HIV-1 group M genome, so a mutation in one region does not produce a false-negative result.

The assay runs on Roche's cobas x800 systems, already used worldwide for more than 10 million tests monthly, with up to 8 hours of walk-away time. By reducing manual steps and human touchpoints, the approach addresses parallel shortages of donations and qualified laboratory staff. For transfusion services, consolidation of viral screening offers a route to faster, more resilient blood supply management without proportional increases in equipment or personnel.