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Specimen Collection and Submission

Changes to Specimen Collection, Shipping, and Testing

As of December 1, 2016, CDC has expanded the search for potential causes of acute flaccid myelitis (AFM) by broadening laboratory approaches that test for potential infectious and noninfectious causes, including possibly immune-mediated mechanisms. Despite extensive pathogen-specific testing of many specimens since 2014, CDC and others have not identified an etiology for the AFM cases. To optimize this new approach, CDC will no longer be performing clinical diagnostics for enteroviruses or metagenomic sequencing on specimens collected from suspect cases of AFM.

To support these new protocols, CDC has changed its collection, storage, and shipping guidance for specimens from AFM cases. Pathogen-specific testing should continue at hospital or state public health laboratories and may include cerebrospinal fluid, sera or whole blood, stool, and respiratory specimens. CDC will prioritize testing of sterile site specimens (i.e., cerebrospinal fluid, blood) using these new protocols to optimize yield of an etiologic agent or possible mechanism for AFM. Non-sterile site specimens, such as respiratory samples, will not be routinely tested at CDC. Stool or fecal specimens should be sent to CDC to rule out the presence of poliovirus. Specimens that are positive for enteroviruses/rhinoviruses at external laboratories may be sent to CDC for typing.

Because the new testing to be done at CDC uses assays that are not CLIA-approved and are not intended for clinical diagnosis, CDC will not be able to provide specific test results for individual samples. Results that indicate a possible cause of AFM will be rapidly disseminated.

Specimen Collection

Clinicians should collect specimens from patients suspected of having AFM as early as possible in the course of illness, preferably on the day of onset of limb weakness. Early specimen collection has the best chance to yield a diagnosis of AFM.

Specimen Submission

CDC advises overnight shipment of available clinical specimens, within 24-48 hours of specimen collection if possible, from patients that meet the clinical case definition to CDC to optimize yield from specialized testing.

State and local health departments and clinicians treating patients with AFM may contact CDC for further laboratory and epidemiologic support by phone through the CDC Emergency Operations Center (770-488-7100), or by email at limbweakness@cdc.gov.

Specimen Collection Specimen submission
Cerebrospinal fluid (CSF) Submit to CDC for testing
Blood (serum and whole blood) Submit to CDC for testing
Stool, preferably two stool specimens collected as soon after onset of limb weakness and separated by 24 hours Submit to CDC for testing
Upper respiratory tract, preferably nasopharyngeal (NP) OR nasal (mid-turbinate [MT]) + oropharyngeal (OP) swab Submit to CDC for testing ONLY if tested positive for enterovirus or rhinovirus at external lab

Additional instructions regarding specimen collection and shipping can be found at AFM Specimen Collection Instructions.

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