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Specimen Collection Instructions

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.

Clinicians should follow these instructions for collecting specimens from patients that meet the clinical case definition for AFM.

  • See Table for further information, optimal timing of specimen collection, minimum volume required, collection and storage, and shipping instructions. Although minimum sample volumes are listed, please send any remaining samples, irrespective of available volume.
  • If specimens have not been collected or all of the available specimens have been utilized and no specimen is remaining, repeating specimen collection is requested, when feasible.

Comments:

  • Please recognize that CDC will not provide specific test results for individual samples since the new testing to be done uses assays that are not CLIA-approved and not intended for clinical diagnosis. However, results that indicate a possible cause of AFM will be rapidly disseminated.
  • CDC appreciates your assistance and participation in this important endeavor. We realize that collection of these specimens may be an added burden on already busy schedules, but through your assistance and cooperation, we hope to gain further insights into the nature of this unusual illness.

*If any of the serum samples that you are sending to CDC were collected after the patient had received intravenous immune globulin (IVIG) or plasmapheresis/plasma exchange, please indicate the date of that therapy on the Patient Summary Form.

Specimens To Collect and Send to CDC for Testing for Suspect AFM Cases

Specimen Type Minimum Amount Collection Storage Shipping Comments
Cerebrospinal fluid (CSF) 2 mL Unspun; standard cryovial tube; collect at same time or within 24 hours as whole blood Refrigerate at 4°C Ship overnight on cold packs. Ship within 24-48 hours of collection* Tubes should be insulated during shipping to ensure they are not in direct contact with cold pack
Cerebrospinal fluid (CSF) 1 mL Spun and processed; standard cryovial tube; collect at same time or within 24 hours as whole blood Freeze at -20°C Ship on dry ice  
Serum 0.4 mL Spun and processed;  Tiger/red top tube Freeze at -20°C Ship on dry ice  
Whole blood 3-5 mL Unspun; lavender/green top tube (with anticoagulant); collect at same time or within 24 hours as CSF Refrigerate at 4°C Ship overnight on cold packs. Ship within 24-48 hours of collection* Tubes should be insulated during shipping to ensure they are not in direct contact with cold pack
Stool Ranked below by first to last preference
1. Whole stool ≥1gram Collect in sterile container, no special medium required Freeze at -20°C Ship on dry ice 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
2. Rectal swab ≥1gram Store in viral transport medium Freeze at -20°C Ship on dry ice 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
Respiratory - NP or nasal (MT)+OP swab 1ml Store in viral transport medium Freeze at -20°C Ship on dry ice Send only if EV/RV positive for typing
In the event of death, please send the following specimens, if possible
Fresh-frozen tissue   Place directly on dry ice or liquid nitrogen Freeze at -70°C Ship on dry ice Representative sections from various organs are requested, but particularly from brain/spinal cord (including gray and white matter), heart, lung, liver, kidney, and other organs as available.
Formalin-fixed or formalin-fixed, paraffin-embedded tissue   Avoid prolonged fixation—tissues should have been fixed in formalin for 3 days, then transferred to 100% ethanol Room temperature Ship at room temperature with paraffin blocks in carriers to prevent breakage See comment above regarding frozen tissue

Footnote

*If specimens cannot be shipped within 24-48 hours of collection, consider recollection, if feasible.

Handling and Shipping

  • 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.
  • For samples that should be sent refrigerated, please store them at 4°C and make arrangements to ship the samples overnight to CDC on cold packs. Samples should not have direct contact with the cold packs during shipping.
  • Samples from each patient should be shipped with completed hard copies of
  • 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.
  • Prior to shipping, please email Will Weldon (wiw4@cdc.gov) and limbweakness@cdc.gov regarding what is being shipped and include the name, phone number and email address of the shipper.

Shipping Address

Dr. Will Weldon
Centers for Disease Control and Prevention
1600 Clifton Road, NE
Building 17, Room 6124
Atlanta, GA 30329
Office: 404-639-5485; Mobile: 404-216-6183; Email: wweldon@cdc.gov

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