05/31/2022: Lab Advisory: CDC Specimen Collection Guidelines for Mpox Virus

CDC's Laboratory Outreach Communication System (LOCS)

CDC issued an update to this message on June 23, 2022. Please refer to the updated message for the most current information.

Audience: Clinical Laboratories

Level: Laboratory Advisory

Laboratories with specimens that are suspected to contain mpox virus should contact their state or territorial public health department (contact list) or the CDC Emergency Operations Center (EOC) at 770-488-7100 for guidance. After consultation, laboratories can send appropriately collected specimens to their state or territorial public health laboratory for real-time polymerase chain reaction (PCR) testing. For more information, see the CDC Laboratory Process for Mpox Virus Testing.

Clinical laboratories should follow these guidelines when collecting specimens for mpox virus:

  • Collect at least two dry swabs from the same lesion.
  • Swab or brush lesion vigorously with two separate sterile dry swabs. Use a sterile nylon, polyester, or Dacron swab with a plastic, wood, or thin aluminum shaft. Do not use other types of swabs.
  • Place swabs in individual sterile containers. Do not add any transport media.
  • Refrigerate (2–8°C) or freeze (-20°C or lower) specimens within an hour after collection. Store refrigerated specimens for up to 7 days and frozen specimens for up to 60 days.
  • Send refrigerated specimens within 7 days of collection; ship frozen specimens within 60 days of collection. Specimens that are greater than 8°C upon receipt will be rejected. Ship on dry ice as category B.
  • Send both swabs to the state or territorial public health laboratory. All specimens should be sent through the state or territorial public health department, unless authorized to send them directly to CDC.
  • A state public health laboratory may test one of the paired dry swabs for presumptive results. CDC can provide mpox virus-specific testing on the second dry swab specimen if the first dry swab is non-variola orthopoxvirus positive at the state or territorial public health laboratory.

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Thank you,

The Laboratory Outreach Communication System

Laboratory Outreach Communication System (LOCS) | Division of Laboratory Systems (DLS)

Center for Surveillance, Epidemiology, and Laboratory Services (CSELS)

Centers for Disease Control and Prevention (CDC)