Specimen Collection Instructions
Because specimen submission requirements for CLIA diagnostic testing are currently being updated, ALL submissions to CDC for diagnostic testing require pre-approval at this time. Please contact AFMLab@cdc.gov before submitting AFM specimens to CDC.
The single case of polio – identified in the United States in July 2022 – reinforces the importance of collecting stool from patients with suspected AFM to rule out polio.
Download and print: How to Report Patients Under Investigation for Acute Flaccid Myelitis.

Specimen Testing Protocols
- CDC will conduct routine testing and typing of CSF, respiratory specimens and stool for enterovirus/rhinovirus, and poliovirus testing of stool specimens to rule out the presence of poliovirus.
- Additional testing protocols are being developed to look for AFM biomarkers and studies to identify possible mechanisms for AFM are underway.
- Pathogen-specific testing should continue at hospital or state public health laboratories and should include CSF, respiratory swab, serum, and stool specimens.
Early Specimen Collection is Critical
Clinicians should collect specimens from patients under investigation (PUIs) for 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 cause of AFM.
Clinicians should:
- Follow the instructions in the table below for collecting specimens from PUIs
- Review How to Report Patients Under Investigation for AFM for more information on how to send information about a PUI.
If specimens have not been collected or all of the available specimens have been used and no specimen remains, you should repeat specimen collection, when feasible.
Sharing Testing Results
- Since the testing protocols include several assays that are not performed under the Clinical Laboratory Improvement Amendments (CLIA) nor intended for clinical diagnosis, CDC will be unable to provide patient-specific results for certain tests that are performed.
- Results following testing of samples from multiple cases that may indicate a possible cause of AFM will be rapidly disseminated.
- Results from certain tests, such as EV/RV testing and typing and stool testing, will be shared with the health department upon completion.
CDC appreciates your assistance and participation in this important endeavor. With your assistance, we hope to gain further insights into the nature of this condition.

Spun and processed; collect at same time or within 24 hours of serum if feasible
Minimum Amount | 0.15 mL, 0.5-2 mL preferred |
Tube Type | Cryovial |
Storage | Freeze at <-20°C |
Shipping | Ship on dry ice |
Results of Testing | Results for EV/RV testing will be returned as testing completed (within 14 days); CSF will also be used for special studies |

Store in viral transport medium
Minimum Amount | 0.5 mL, 1 mL preferred |
Tube Type | N/A |
Storage | Freeze at <-20°C |
Shipping | Ship on dry ice |
Results of Testing | EV/RV testing and typing will be performed and results returned within 14 days of sample receipt |

Spun and processed; send aliquot; collect at same time or within 24 hours of CSF if feasible
Minimum Amount | 0.5 mL, 1 mL preferred |
Tube Type | Tiger/red top for collection; separate tube for shipping |
Storage | Freeze at <-20°C |
Shipping | Ship on dry ice |
Results of Testing | Results for EV/RV testing will be returned as testing completed (within 14 days); Serum will also be used for special studies |

Two samples total, collected at least 24 hours apart, both collected as early in illness as possible and ideally within 14 days of illness onset
Minimum Amount | 1 gram, 10 – 20 grams preferred |
Tube Type | Sterile container; Not a rectal swab†. |
Storage | Freeze at <-20°C |
Shipping | Ship on dry ice |
Results of Testing | Results for EV/RV and poliovirus testing will be returned as testing completed (within 14 days) |
*If any of the serum samples that you are sending to CDC were collected after the patient had received intravenous immune globulin (IVIG), steroid treatments, or plasmapheresis/plasma exchange, please indicate the date of that therapy on the Patient Summary Form.
† The negative predictive value is very low for rectal swabs since the amount of fecal material collected is much less than for stool.
Reporting Job Aid for Clinicians: Reporting Patients Under Investigation for Acute Flaccid Myelitis (cdc.gov)
Prior to shipping, send an email regarding what is being shipped and include the name, phone number and email address of the shipper.
Please send this information to the following mailboxes:
State and local health departments and clinicians treating PUIs may contact CDC for further laboratory and epidemiologic support by phone through the CDC Emergency Operations Center (770-488-7100), or by email at AFMinfo@cdc.gov (epidemiology information) or by email at AFMLab@cdc.gov (laboratory information).
- Overnight shipping: CDC advises overnight shipment of available clinical specimens from patients under investigation (PUIs) for AFM to CDC to optimize yield from specialized testing.
- Arrive Tuesday through Friday: Please ship specimens overnight so they arrive at CDC on Tuesday through Friday. Do not ship specimens on Friday or over the weekend.
- For samples that should be frozen: Please freeze them at ≤-20°C and make arrangements to ship the samples overnight to CDC frozen on dry ice.
- Include Patient Forms: Samples from each patient should be shipped with completed hard copies of
- The AFM Patient Summary Form AND
- A specimen submission form for each specimen submitted. Please note: for Test Order Name, please select “Picornavirus Special Study”.
- If 10 or more patient specimens are submitted: Please provide an electronic line listing by email. Use the following headers in this order: patient ID number; date of birth; sex; onset date; fatal y/n; specimen ID number; specimen collected date; specimen type; if culture isolate—cell line and passage number.
Shannon Rogers
Centers for Disease Control and Prevention
RDSB/STAT Unit 76
ATTN: Polio and Picornavirus Laboratory Branch
1600 Clifton Road, NE
Atlanta, GA 30329
Office: +1-404-639-2677
Mobile: +1-678-520-6455
Email: AFMLab@cdc.gov
Specimens to Collect and Send to CDC for Testing in the Event of Death
In the event of death, please send the following specimens, if possible.
Pre-approval Required | In the event of death, prior to shipping, please contact the Infectious Diseases Pathology Branch (IDPB) at pathology@cdc.gov for pre-approval to submit formalin-fixed tissues |
Collection & Storage |
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Shipping |
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Additional Information | IDPB’s specimen requirements and specimen submission instructions, including shipment address, is available at: https://www.cdc.gov/laboratory/specimen-submission/detail.html?CDCTestCode=CDC-10365 |
Pre-approval Required | Fresh-frozen tissues may be acceptable under limited circumstances. In the event of death, prior to shipping, please contact the Infectious Diseases Pathology Branch (IDPB) at pathology@cdc.gov for pre-approval to submit fresh-frozen tissues |
Collection & Storage |
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Shipping |
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Additional Information | IDPB’s specimen requirements and specimen submission instructions, including shipment address, is available at: https://www.cdc.gov/laboratory/specimen-submission/detail.html?CDCTestCode=CDC-10560 |
Handling and Shipping
Prior to shipping, please contact Infectious Diseases Pathology Branch (IDPB) at pathology@cdc.gov for pre-approval of specimen submission.
Additional information on IDPB’s specimen requirements and specimen submission instructions, including shipment address, is available at: https://www.cdc.gov/laboratory/specimen-submission/detail.html?CDCTestCode=CDC-10365
Contact us with questions
State and local health departments and clinicians treating PUIs may contact CDC for further laboratory and epidemiologic support by:
- Phone: CDC Emergency Operations Center (770-488-7100)
- Email: AFMinfo@cdc.gov (epidemiologic support)
- Email: AFMLab@cdc.gov (laboratory support)