The U.S. Centers for Disease Control and Prevention (CDC) recommended that all laboratories performing mpox testing send certain types of clinical specimens to a laboratory that can perform clade-specific testing as quickly as possible.
In the alert issued August 27, the CDC also advised that due to mutations that may impact clade-specific polymerase chain reaction (PCR) tests, laboratories should use a test that targets a viral essential gene (e.g., the CDC NVO test) as part of a testing strategy to ensure that mpox cases are not missed.
For all laboratories performing mpox testing using an orthopoxvirus or monkeypox virus (MPXV) generic test without any additional clade-specific testing occurring, the CDC specified clinical specimen types as those collected from patients who traveled from the Democratic Republic of the Congo (DRC), its neighboring countries, or any country with clade I mpox cases. Additionally, the CDC said to also route clinical specimens from those who have had close or intimate contact with symptomatic people from these countries.
Additionally, if clade-specific testing is warranted but is not available in a jurisdiction, specimen submission to a capable public health laboratory or to the CDC is encouraged, the CDC said.
Laboratories using the CDC’s nonvariola orthopoxvirus (NVO) test should continue submitting the duplicate specimen to the CDC from all patients with positive NVO test results for routine MPXV clade-specific testing if they are not performing clade-specific testing in their laboratory, according to the CDC. Specimens that cannot be accepted at the CDC for clinical testing under Clinical Laboratory Improvement Amendments (CLIA) will be redirected for surveillance purposes and tested, providing critical data on MPXV clade(s) circulating in the United States.
More information can be found here.
