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Mpox Virus DNA, Qualitative Real-Time PCR 

Test Code: 12084

The Mpox Virus DNA, Qualitative Real-Time PCR test is a laboratory-developed assay from Quest. This multiplex polymerase chain reaction (PCR) assay detects DNA of non-variola orthopoxviruses (NVOs) (ie, Vaccinia virus and Mpox virus) and the clade II (formerly known as the West African strain) of the Mpox virus. This assay does not detect Variola virus, the causative agent of smallpox.

The Quest Mpox test can detect subclade Ib, but the result must be confirmed. The Quest Mpox test is a dual-target assay. One target detects non-variola orthopoxviruses (NVOs) DNA, including clade I, while the second target detects clade II (formerly known as the West African strain of mpox) DNA. Thus, if the test is positive for the first target (both clades) and negative for the second target (clade II), the specimen is referred to a public health laboratory for additional testing and confirmation of clade I.

The Quest Mpox Virus DNA, Qualitative Real-Time PCR is a CLIA laboratory-developed assay that is based on the CDC targets for the NVOs as well as clade II (formerly known as the West African strain) of the Mpox virus. 1,2 It has been designed for high-throughput, specific testing. The CDC NVO Real-Time PCR Primer and Probe set has been granted 510K clearance by the FDA.

The key differences between the Quest Mpox virus DNA, Qualitative Real-Time PCR and the CDC NVO DNA test are the following:

  1. Target: The Quest-developed Mpox Virus DNA test is a dual-target assay. It can detect NVO DNA and detect the clade II (formerly known as the West African strain of Mpox) DNA. Therefore, confirmatory testing is not needed (unless suspected clade Ib) with the dual target Mpox Virus DNA, Qualitative Real-Time PCR test.3 The CDC NVO assay targets NVOs (see Table below).
  2. Specimen type: The Quest Mpox Virus DNA, Qualitative Real-Time PCR test is performed from specimens collected in viral transport media; the liquid media, not the swab, is used for testing. The CDC NVO PCR protocol requires that either a dry swab or a swab in media be processed for testing. Because the CDC protocol includes processing of the swab and not testing of the media, 2 swabs per lesion need to be collected so that 1 swab can be sent to the CDC for additional confirmatory testing if the NVO PCR is positive.
Table. Molecular Targets of the Quest Mpox Virus DNA, Qualitative Real-Time PCR Test and the CDC non-Variola Orthopoxvirus DNA Test

Swab a pustule/lesion vigorously and place the swab into a viral culture media (VCM) or equivalent tube.

No additional confirmatory testing is required at the CDC; therefore, a duplicate swab from the same lesion is not needed. If clinically indicated, consider submitting additional swabs if multiple lesions with different stages are present. Multiple specimens collected from a single patient should be submitted separately; each should be accompanied by its own separate requisition and transported in its own sealed bag. Ship frozen (preferred) or refrigerated.

Healthcare personnel should collect specimens using personal protective equipment (PPE) in accordance with recommendations for healthcare settings.4 Specimens will not be collected in Quest patient service centers.

For additional information please read the Mpox specimen collection guidelines (questdiagnostics.com)

Quest VCM is equivalent to Copan Universal Transport Medium (UTM), BD Universal Viral Transport (UVT), Cepheid XPert Sample Collection Kit for Viruses, and Hardy-Health Link UTM. These media are manufactured in identical fashion; all raw materials utilized across all products are equivalent and present at the same ratios. 

Yes, the Quest Mpox Virus DNA, Qualitative Real-Time PCR test received EUA from the FDA on September 7, 2022.5

Yes. The FDA has provided guidance regarding requests for EUA and notification of modifications made to Mpox tests after an EUA has been issued.  Please refer to the following FDA document for more details: FDA.gov/Media/161443/Download.6

The only modification to the Quest Mpox Virus DNA, Qualitative Real-Time PCR test since it received EUA from the FDA on September 7, 2022, is the verification of an alternative positive control. The positive control has been modified to a pool of leftover, deidentified, positive patient specimens in buffer, which more accurately simulates a patient specimen. This modification would not have any impact on patient results.

References

  1. Li Y, Olson VA, Laue T, et al. Detection of monkeypox virus with real-time PCR assays. J Clin Virol. 2006;36(3):194-203. doi:10.1016/j.jcv.2006.03.012
  2. Li Y, Zhao H, Wilkins K, et al. Real-time PCR assays for the specific detection of monkeypox virus West African and Congo Basin strain DNA. J Virol Methods. 2010;169(1):223-227. doi:10.1016/j.jviromet.2010.07.012
  3. Biosafety Laboratory Guidance for Handling and Processing Mpox specimens. Centers for Disease Control and Prevention. Updated June 20th, 2024. Accessed September 12, 2024. Laboratory Procedures | Mpox | Poxvirus | CDC. 
  4. Infection prevention and control of monkeypox in healthcare settings. Centers for Disease Control and Prevention. Updated August 2, 2024. Accessed September 12, 2024.  https://www.cdc.gov/poxvirus/monkeypox/clinicians/infection-control-healthcare.html
  5. Bumpus, NN. Quest Diagnostics Monkey Pox Virus Qualitative Real-Time PCR – letter of authorization. US Food and Drug Administration. Published September 7, 2022. Accessed September 12, 2024. https://www.fda.gov/media/161454/download
  6. Policy for Monkeypox tests to address the public health emergency: guidance for laboratories, commercial manufacturers, and Food and Drug Administration staff. US Food and Drug Administration. Published September 7, 2022. Accessed September 12, 2024 www.fda.gov/media/161443/download

 

This product has not been FDA cleared or approved, but has been authorized for emergency use by FDA under an EUA for use by the authorized laboratories;

 

This product has been authorized only for the detection of nucleic acid from mpox virus or other non-variola orthopoxviruses, not for any other viruses or pathogens; and

 

The emergency use of this product is only authorized for the duration of the declaration that circumstances exist justifying the authorization of emergency use of in vitro diagnostics for detection and/or diagnosis of infection with the mpox virus, including in vitro diagnostics that detect and/or diagnose infection with non-variola Orthopoxvirus, under Section 564(b)(1) of the Federal Food, Drug, and Cosmetic Act, 21 U.S.C. § 360bbb-3(b)(1), unless the declaration is terminated or authorization is revoked sooner.

 

This FAQ is provided for informational purposes only and is not intended as medical advice. Test selection and interpretation, diagnosis, and patient management decisions should be based on the physician’s education, clinical expertise, and assessment of the patient.

 

Document FAQS.286 Version: 5

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Version 4: Effective 07/31/2023 to 09/12/2024

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Version 1: Effective 07/28/2022 to 08/29/2022

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