Poxvirus PCR

TEST DESCRIPTION

The poxvirus polymerase chain reaction (PCR) detects DNA from non-variola orthopoxviruses, including vaccinia, cowpox, mpox, and ectromelia viruses. Specimens that test positive for orthopoxvirus nucleic acid are considered presumptively positive for an orthopoxvirus and such specimen(s) may be referred for confirmatory testing.   

Methodology

PCR

Reference range

Negative

TEST FREQUENCY & RESULT AVAILABILITY

Performed daily. Results are typically available one business day after specimen receipt.

ACCEPTABLE SPECIMEN TYPES AND COLLECTION

• Preferred: Dry swabs (×2) of a single lesion in a sterile container
• Swab of a single lesion in viral transport medium (VTM)
• Detailed collection instructions appear below

SPECIMEN STORAGE

Refrigerate (2–8°C) dry swabs within an hour after collection. Store at refrigerated temperatures for up to 7 days.  

SPECIMEN TRANSPORT

Shipping conditions should follow the temperature and time requirements outlined above. Transport should occur on wet ice.

REJECTION CRITERIA

• Holding time greater than 7 days at refrigerated temperature
• Incomplete specimen labeling/documentation
• Improperly stored specimens 
• Specimen tubes/containers not sealed properly

CODES

CPT: 87798
LOINC: 100434-0
Test code: BTC05300

TEST FEE

Refer to the current fee schedule.

DETAILED SPECIMEN COLLECTION INSTRUCTIONS

1. Personal protective equipment (PPE) should be worn when collecting a specimen from a person with suspected or confirmed mpox. Recommended PPE consists of a gown, gloves, eye protection (e.g., face shield), and a NIOSH-approved particulate respirator with an N95 filter or higher.
2. Do not clean the lesion before sample collection. Also, do not apply a numbing cream or topical agent prior to swabbing as this may interfere with testing results.
3. More than one lesion should be sampled, preferably 2 to 3 total lesions (for 2 to 3 total specimens) if present on different body sites. 
   1. Use a sterile, dry, synthetic swab (e.g., nylon, polyester or Dacron swab) to sample a lesion.
   2. Vigorously swab or brush each lesion with a sterile dry swab.
   3. Break off swab and place it into a sterile tube or container.
      1. Label the tube or container with the patient’s full name, date of collection, and specimen source.
      2. For swabs stored dry (preferred): The same lesion should be sampled with two separate swabs. Place each swab in its own sterile container, then put both containers into a single specimen biohazard bag.
      3. For swabs stored wet: A lesion can be sampled with a single swab. Place the swab into a collection vial with 2–3 ml of VTM and put the vial into a specimen biohazard bag.
   4. Fill out the San Luis Obispo Public Health Laboratory Requisition completely.
      1. Indicate on requisition that you are requesting Poxvirus testing.
      2. Place the completed requisition in the pocket (not inside) of the specimen biohazard bag.
4. Note: If testing is needed for other viral causes of rash, separate collection is required. Preferred specimen types by virus are as follows: 
   1. Varicella-Zoster Virus and Herpes Simplex Viruses: Swab specimens from cutaneous and mucocutaneous lesions in VTM or universal transport medium (UTM).
   2. Enterovirus: Nasopharyngeal swab in VTM.