Clinical laboratories may need to reassess their readiness to perform molecular testing for measles and other vaccine-preventable diseases as outbreaks continue across the United States.
On Aug. 24, 2026, the College of American Pathologists (CAP) will launch its Measles, Mumps, Rubella, and Varicella-Zoster Virus Molecular Proficiency Testing program. The program is designed to help microbiology and public health laboratories evaluate the accuracy of their molecular assays under conditions that resemble routine clinical workflows.
The launch comes as public health officials continue to assess whether prolonged measles transmission could threaten the nation’s elimination status. The US declared measles eliminated in 2000, meaning continuous domestic transmission had been interrupted for at least 12 months. However, imported infections can still trigger outbreaks in communities with low vaccination coverage.
The United States has recorded 2,295 measles cases in 2026, surpassing the 2025 total and reaching the highest annual level in 35 years with more than five months remaining, according to The Hill. The surge, concentrated largely among unvaccinated people, has intensified concerns that the nation could lose its measles elimination status.
For laboratory leaders, the resurgence highlights the challenge of maintaining competency for tests that may be ordered infrequently during normal operations but become critical during an outbreak.
“Molecular testing can make the difference between a rapid, confident diagnosis and unnecessary uncertainty during an outbreak,” said CAP President Qihui “Jim” Zhai, MD, FCAP, in a statement. “This proficiency testing program gives laboratories the opportunity to demonstrate readiness for infrequent but high-consequence events and helps ensure they can deliver reliable results when testing demand surges.”
Molecular testing adds speed and specificity
Molecular testing can directly detect viral RNA, allowing laboratories and public health agencies to confirm cases more quickly than virus culture. The Centers for Disease Control and Prevention considers real-time reverse transcription polymerase chain reaction testing a preferred method of measles confirmation, although results depend heavily on specimen timing, quality, and handling.
Molecular methods also can help distinguish wild-type measles infection from a reaction following recent vaccination. This distinction can be especially important when a recently vaccinated patient develops fever or a rash, symptoms that could otherwise trigger unnecessary isolation measures, contact investigations, and public health interventions. CDC’s vaccine-specific MeVA assay can identify vaccine strains in approximately two hours when used alongside a standard measles RT-PCR assay.
CAP said its integrated program covers measles, mumps, rubella, and varicella-zoster virus and closely mirrors clinical laboratory workflows. Participants can use the proficiency testing materials to assess assay performance, identify weaknesses in testing processes, and demonstrate ongoing competency.
The broader laboratory implications extend beyond analytical accuracy. Labs preparing for possible outbreaks should review specimen collection guidance, transportation procedures, staffing plans, reporting protocols, referral arrangements, and communication pathways with infection prevention teams and public health departments.
Measles is immediately reportable, and CDC recommends collecting respiratory or urine specimens for molecular testing along with serum for serology from patients with compatible symptoms.
For clinical laboratory managers, proficiency testing may provide an opportunity to identify operational gaps before a suspected case arrives—when accurate results, rapid turnaround times, and timely public health notification can directly influence outbreak containment.
This article was created with the assistance of Generative AI and has undergone editorial review before publishing.
