CDC rejects measles assay validation requested by West Coast officials

Public health laboratories still rely on lower-volume PCR testing

California and Washington asked the US Centers for Disease Control and Prevention in May to validate a new measles-testing method, according to a West Coast Health Alliance letter to CDC Director Erica Schwartz. The letter said the CDC denied the request after a two-month wait, citing “other competing priorities.” Health officials from California, Hawaii, Oregon and Washington signed the letter.

The officials asked Schwartz to reconsider and validate the assay in preparation for major outbreaks. They also asked the CDC to create protocols for testing other high-priority pathogens, extending the request beyond measles.

US Department of Health and Human Services spokesperson Emily Hilliard said the CDC was “ensuring state and local health departments have the support needed to strengthen measles detection and outbreak response.” The agency is “prioritizing emerging technologies” to respond to the measles outbreak, Hilliard said.

Hilliard did not answer whether the CDC had plans to validate a high-throughput measles assay. Public health laboratories currently rely on lower-volume methods for measles, including individual polymerase chain reaction tests.

During the Covid pandemic, most public health laboratories bought high-volume equipment such as the Hologic Panther Fusion. The polymerase chain reaction platform for diagnosing illness can process up to 500 tests in eight hours, allowing laboratories to process large batches of Covid tests very quickly.

There is no high-throughput measles diagnostic test published or validated by the CDC. Texas state laboratories developed such a test during the 2025 West Texas outbreak, but they have not distributed or published its protocol.

The alliance said the CDC could implement and publish the Texas protocol, or another protocol, so other public health laboratories could run diagnostic tests. Officials said in the letter that the CDC had reportedly completed studies of the Texas test and another test from ARUP Laboratories, “but they were not full validations or a comprehensive comparison.”

The alliance asked Schwartz to develop an assay, or test, for measles diagnostic testing on the Panther Fusion and publish its protocol so any laboratory could run the tests. The officials said such a test would “dramatically strengthen” laboratories’ ability to respond quickly to outbreaks and help preparedness for known pathogens such as Ebola or hantavirus, as well as emerging threats.

The letter said having tests ready to go was an essential part of preparedness. It warned: “If a large outbreak were to occur in our region, without high-throughput capacity, it would be more difficult to scale up diagnostic testing appropriately, impairing patient care and public health investigation.”