Orthopoxvirus (includes mpox) by PCR

Abbrev Code:OPOXPCR   
Order Code:LAB8262Order Name:Orthopoxvirus (includes mpox) by PCR
Methodology:Qualitative polymerase chain reaction
CPT Codes: 87593 x1, 87593 x1
Turnaround Time:Results are available within 2-4 days. Test performed 7 days/week.
Special Instructions:Sending laboratory should indicate "Suspected mpox" on the specimen bag.
Associated Links:

Include ARUP Patient Demographic Form for Public Health Reporting for each patient

Collection Instructions

Specimen:Swab of lesion
Container:Viral Transport Media
Alternate Containers: floQ dry swabs
Collection Instructions:An order is required for each lesion collected using a separate container and swab. If multiple specimens are being submitted, record specimen source on collection container. Swab the lesion vigorously to collect adequate DNA. It is not necessary to deroof the lesion before swabbing.
  • Preferred: Use Viral Transport Media, swab lesion, then place into VTM.
  • If VTM is unavailable, use one dry swab per lesion (including, but not limited to polyester, nylon or Dacron swab). Place swab into sterile container.
Causes for Rejection:Calcium alginate swab, wooden swab. Specimens without swabs.

Processing and Shipping

Shipping Instructions:Ship at frozen temperature.
Include ARUP Patient Demographic Form for Public Health Reporting for each patient. See Associate Links section.
Stability:Frozen stability is 7 days.
Test Performed at or Referral Lab Lab Sendouts  (ARUP)
Referral Lab number:3005716


Use:This assay does not differentiate members of the orthopoxviruses. In the United States, a detected result is most likely due to mpox virus or vaccinia virus. Other orthopoxviruses may be considered if appropriate. Refer to the US Centers for Disease Control and Prevention if additional confirmatory testing is needed.

Mpox, an Orthopoxvirus, is a zoonotic infection endemic to several Central and West African countries and is related to the virus that causes smallpox. Before May 2022, cases outside of Africa were reported either among people with recent travel to those countries or contact with a person with a confirmed mpox virus infection.

Symptoms of mpox include fever, headache, muscle aches, swollen lymph nodes, and a rash that resembles pimples or blisters. Mpox is spread from person to person through direct contact with rash, scabs, or body fluid or by respiratory secretions during close contact (eg, kissing, cuddling, or sexual contact). Mpox may also be spread through contact with shared objects such as linens, towels, or sexual implements.  Pregnant individuals may also transmit the virus to a fetus through the placenta. Mpox is diagnosed using a polymerase chain reaction (PCR)-based assay to detect mpox virus DNA, or in some situations, orthopoxvirus DNA.

Per CDC’s Definitions:
Suspect Case
  • New characteristic rash* OR
  • Meets one of the epidemiologic criteria and has a high clinical suspicion† for mpox

Probable Case
  • No suspicion of other recent Orthopoxvirus exposure (e.g., Vaccinia virus in ACAM2000 vaccination) AND demonstration of the presence of
    • Orthopoxvirus DNA by polymerase chain reaction of a clinical specimen OR
    • Orthopoxvirus using immunohistochemical or electron microscopy testing methods OR
    • Demonstration of detectable levels of anti-orthopoxvirus IgM antibody during the period of 4 to 56 days after rash onset

Confirmed Case
  • Demonstration of the presence of Mpox virus DNA by polymerase chain reaction testing or Next-Generation sequencing of a clinical specimen OR isolation of Mpox virus in culture from a clinical specimen

Epidemiologic Criteria
Within 21 days of illness onset:
  • Reports having contact with a person or people with a similar appearing rash or who received a diagnosis of confirmed or probable mpox OR
  • Had close or intimate in-person contact with individuals in a social network experiencing mpox activity, this includes men who have sex with men (MSM) who meet partners through an online website, digital application (“app”), or social event (e.g., a bar or party) OR
  • Traveled outside the US to a country with confirmed cases of mpox or where Mpox virus is endemic OR
  • Had contact with a dead or live wild animal or exotic pet that is an African endemic species or used a product derived from such animals (e.g., game meat, creams, lotions, powders, etc.)

Exclusion Criteria
A case may be excluded as a suspect, probable, or confirmed case if:
  • An alternative diagnosis* can fully explain the illness OR
  • An individual with symptoms consistent with mpox does not develop a rash within 5 days of illness onset OR
  • A case where high-quality specimens do not demonstrate the presence of Orthopoxvirus or Mpox virus or antibodies to orthopoxvirus

†Clinical suspicion may exist if presentation is consistent with illnesses confused with mpox (e.g., secondary syphilis, herpes, and varicella zoster).

*The characteristic rash associated with mpox lesions involve the following: deep-seated and well-circumscribed lesions, often with central umbilication; and lesion progression through specific sequential stages—macules, papules, vesicles, pustules, and scabs.; this can sometimes be confused with other diseases that are more commonly encountered in clinical practice (e.g., secondary syphilis, herpes, and varicella zoster). Historically, sporadic accounts of patients co-infected with Mpox virus and other infectious agents (e.g., varicella zoster, syphilis) have been reported, so patients with a characteristic rash should be considered for testing, even if other tests are positive.   Categorization may change as the investigation continues (e.g., a patient may go from suspect to probable).

Additional information: Mpox is an Orthopoxvirus , the same genus as smallpox, variola and vaccinia viruses. Incubation period is generally between 7-17 days. Clinical disease is very similar to smallpox and starts with a prodromal phase of 1-4 days consisting of fever, headache, and fatigue. Lymphadenopathy may occur as well. However, in the most recently reported cases, prodromal symptoms have not always occurred, and some cases only had lesions in the genital and perianal region, without other symptoms. The rash is well circumscribed, hard, deep-seated and umbilicated.

A person is infectious from symptom onset until lesions have crusted, those crusts have separated, and a fresh layer of healthy skin has formed underneath. Human-to-human transmission occurs through direct contact with body fluids or lesion material, or prolonged contact with respiratory droplets. Indirect contact with lesion material through fomites has also been documented. Animal-to-human contact may occur through a bite or scratch, preparation of wild game and direct or indirect contact with body fluids or lesion material.

There is no specific treatment for mpox virus infection, although antivirals developed for use in patients with smallpox may prove beneficial. Persons with direct contact (e.g., exposure to the skin, crusts, body fluids, or other materials) or indirect contact (e.g., presence within a six foot radius in the absence of an N-95 or filtering respirator for ≥3 hours) with a patient with mpox should be monitored by health departments, depending on their level of risk, some persons may be candidates for post-exposure prophylaxis with smallpox or mpox vaccine under an Investigational New Drug protocol after consultation with public health authorities.

Note: as of November 2022, the World Health Organization renamed monkeypox as mpox to avoid potential stigma associated with the name. WHO officials said the use of the new term will be phased in over a year.  

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