The monkeypox virus is an Orthopoxvirus. The variola virus, which causes smallpox and has been eradicated globally, is another type of Orthopoxvirus. Monkeypox is a non-variola Orthopoxvirus and is generally not fatal.  It typically resolves on its own without treatment. The current outbreak in the U.S. usually presents as a rash on the body, face, or genital area. Although there is a very low risk of death, there have been reported complications including severe pain, at times requiring hospital admission.

On August 9, 2022, the Secretary of the Department of Health and Human Services (HHS) determined, pursuant to section 564 of the Federal Food, Drug, and Cosmetic (FD&C) Act, that there is a public health emergency, or a significant potential for a public health emergency, that affects, or has a significant potential to affect, national security or the health and security of United States citizens living abroad that involves monkeypox virus.

On the basis of this determination, on September 7, 2022, the Secretary of HHS subsequently declared that circumstances exist justifying the authorization of emergency use of in vitro diagnostics for the detection and/or diagnosis of infection with the monkeypox virus, including in vitro diagnostics that detect and/or diagnose infection with non-variola Orthopoxvirus, pursuant to section 564 of the FD&C Act, subject to the terms of any authorization issued under that section.

Information on Emergency Use Authorizations (EUAs) for in vitro diagnostics that the FDA has issued related to monkeypox to address the public health emergency is available on the Monkeypox EUAs web page.

Monkeypox Tests (In Vitro Diagnostic (IVD) Devices)

Monkeypox virus diagnostic tests are used to determine if a person is infected with the virus that causes monkeypox, which is a type of Orthopoxvirus.

The Centers for Disease Control and Prevention (CDC) has an FDA-cleared real-time polymerase chain reaction (PCR) test that detects non-variola Orthopoxvirus DNA, including monkeypox virus (the CDC test):

• CDC Non-variola Orthopoxvirus Real-time PCR Primer and Probe Set (see below for regulatory history of CDC test))

The CDC test is available in designated CDC Laboratory Response Network (LRN) and other CDC-designated laboratories.

HHS has taken several actions to quickly increase monkeypox testing capacity and access. In June 2022, HHS, through the CDC, began shipping the CDC test to five commercial laboratory companies. FDA cleared the use of additional reagents and automation, which helped to increase testing capacity of laboratories using the CDC test.

History of CDC's Non-Variola Orthopoxvirus Diagnostic Tests

A CDC test was cleared in 2018 (K181205) for in vitro qualitative presumptive detection of non-variola Orthopoxvirus DNA extracted from human pustular or vesicular rash specimens and viral cell culture lysates submitted to an LRN reference laboratory.

In 2022, the FDA cleared additional 510(k)s from CDC, which expanded testing capacity through use:

• of additional reagents and automation (K221658; cleared on June 10, 2022),
• in CDC-designated laboratories outside the LRN (K221834; cleared on June 24, 2022), and
• of new extraction platform options, among other changes (K222558; cleared on August 30, 2022).

In addition, separate from its cleared test, the CDC published a real-time PCR test procedure (PDF) to detect non-variola Orthopoxvirus DNA.

Laboratory Developed Tests

There may also be laboratory developed tests (LDTs) available for non-variola Orthopoxvirus or specifically for monkeypox. An LDT is a type of in vitro diagnostic test that is designed, manufactured, and used within a single site CLIA-certified laboratory that meets the requirements for high complexity testing.

The FDA has generally exercised enforcement discretion with respect to LDTs, including those developed by hospitals or academic laboratories, meaning that, except in certain circumstances, the FDA generally does not exercise its authority to enforce the regulatory requirements for these devices, although it maintains that authority.

The FDA has not applied this general enforcement discretion approach to tests used for declared emergencies under Section 564 of the Federal Food, Drug, and Cosmetic Act (FD&C Act).  In the case of a contagious disease, for example, inaccurate tests can lead to greater spread of the disease and impede the public health response. The FDA, therefore, has generally expected EUAs for LDTs during all prior declared public health emergencies, starting with H1N1 in 2009 and continuing through the COVID-19 emergency. However, in issuing policies for specific emergencies, the FDA has considered the national testing needs, availability of cleared or authorized tests, and consequences of a false result, among other factors, and has tailored its specific enforcement discretion policies accordingly.   

In line with these considerations, to address current public health needs, the FDA has issued the Policy for Monkeypox Tests to Address the Public Health Emergency (discussed further below), which includes enforcement discretion policies for certain monkeypox tests developed by laboratories. These policies do not apply to at-home tests, tests with home specimen collection, and tests performed outside of a high-complexity CLIA-certified laboratory. For purposes of the guidance, "high-complexity CLIA-certified laboratories" are referring to single site laboratories that are certified under CLIA that meet the requirements to perform tests of high-complexity. The FDA will continue monitoring the developing situation and will evaluate whether there is a need to implement or adjust our policies for LDTs and other tests for monkeypox based on the public health needs and taking into account lessons learned from COVID-19.

Information for test developers

The guidance, Policy for Monkeypox Tests to Address the Public Health Emergency, issued on September 7, 2022, describes:

• Review priorities of emergency use authorization (EUA) requests for monkeypox diagnostic tests,
• Enforcement policies for certain diagnostic tests that are developed by and performed in a laboratory certified under the Clinical Laboratory Improvement Amendments (CLIA) that meets the requirements to perform tests of high complexity,
• Enforcement policies for FDA-cleared or authorized monkeypox diagnostic tests that are modified,
• Enforcement policies for certain serology tests, and
• Recommendations for diagnostic test validation.

Additional Information

• Policy for Monkeypox Tests to Address the Public Health Emergency
• Monkeypox Emergency Use Authorizations (EUAs) for Medical Devices
• FAQs on Testing for Monkeypox
• CDC Information for Laboratory Personnel
• For Monkeypox Testing, Use Lesion Swab Samples to Avoid False Results: FDA Safety Communication
• FDA Monkeypox Response
• CDC Monkeypox