Mpox Commercial Testing and State Lab Testing Criteria

Timely testing of persons with clinical suspicion of mpox, especially those with known exposures or are connected to a congregate care facility, is critical to containing the outbreak. Providers are reminded to submit specimens to an IDPH laboratory for persons who attend or work in a congregate setting, including long-term care facilities, schools, day cares, and jails. Additional guidance is provided below.

For patients not linked to a congregate setting, commercial lab testing for mpox is available at Labcorp, Quest Diagnostics, Aegis Science, Mayo Clinic Laboratories, Sonic Healthcare, and ARUP. (Mayo Clinic is performing mpox testing but only through health care providers who use Mayo Clinic Laboratories as their reference lab.)  Health care providers should order testing for patients meeting clinical criteria through these laboratories. Although local health department (LHD) approval for testing is not necessary for commercial lab testing, notify your LHD about suspect cases for whom you are pursuing mpox diagnostic testing at a commercial laboratory - unless directed otherwise by your LHD (e.g., notification for testing at commercial labs for Chicago or Cook County residents is not required).

Positive test results should be combined with clinical presentation and patient risk factors. Molecular testing is extremely sensitive and the potential for cross-contamination exists during testing raising the potential for false-positive results. To ensure accurate reporting of clinical results, the Centers for Disease Control and Prevention (CDC) recommends that positive specimens with high amplification values (low positive results) are re-extracted and re-tested prior to releasing a final test result.  However, this is only a recommendation and is not enforceable.  Therefore, if a laboratory provides a positive test result that is not consistent with clinical presentation or associated risk factors, it is recommended that providers, referring laboratories, and public health professionals contact the testing laboratory to request an analytical recheck of the test results and, if necessary, a re-test of the original patient specimen.

Patients should be told to isolate until results are known and, if positive, until all sores have healed, and a fresh layer of skin has formed. Providers are to collect two samples from a lesion using sterile dry polyester, rayon, or Dacron swabs that should be readily available in most offices.

Testing at IDPH laboratories will be limited to priority cases and will continue to require the approval of LHDs for both testing criteria and need for priority testing. Criteria for testing at IDPH laboratories are as follows:

• Urgent test based on clinical picture, including but not limited to:
  • Severe disease (e.g., hemorrhagic disease, confluent lesions, sepsis, encephalitis, or other conditions requiring hospitalization)
  • Individuals with likely mpox infections in unusual anatomical sites (e.g., eyes or mouth)
  • Individuals being considered for Tecovirimat, imminently for any other clinical reason
• Urgent test based on individual risk:
  • Those at risk of severe disease (e.g., immunocompromised; pediatric populations, especially <8 years of age; pregnant or breastfeeding people; individuals with one or more complications)
  • Inability to be tested elsewhere due to expense of testing or for those in the process of establishing commercial testing lab
• Urgent test based on epidemiological risk:
  • Public health concern requiring prompt follow-up action (e.g., jails, homeless shelters, skilled nursing facilities, schools)
  • Other situation deemed by the LHD as warranting testing at the state lab

If testing at IDPH laboratories is not approved and mpox is suspected, providers should seek testing at a commercial laboratory. Providers should report patients testing positive via commercial labs to their LHD by phone within three hours of notification so the patient can be instructed to isolate and take measures to protect others around them from becoming infected.  Additionally, Labcorp and Mayo Clinic results will be imported into I-NEDSS via Electronic Lab Reporting (ELR). Results that are “Detected,” “Equivocal,” or “Inconclusive” will come to LHDs via their Lab/Provider queue. Not Detected results will also be imported and can be accessed by changing the “Report Status” filter in Lab/Provider Reports to “Potentially Reportable” or while in a suspect case, clicking “Find New Lab & Provider Reports.”

Clinicians working in outpatient clinics may be first to evaluate patients with suspect mpox as many patients have mild symptoms. Mpox may be confused with sexually transmitted infections and varicella zoster virus infections, as well as many other rash illnesses. Diagnosis of another sexually transmitted infection does not exclude mpox infection; infections may be concurrent. Providers are urged to:

• Obtain sexual and travel history
• Determine if any contacts have/had a similar rash
  
• Be vigilant to the possibility of mpox if characteristic rash is present
  
• Use appropriate personal protective equipment
  

Providers should report to their local health department within three hours for any suspect or lab confirmed mpox cases who are employed or attend/reside in a congregate setting (e.g., homeless shelter, senior facility, correctional facility, university dorm, day care, or school) or other situation that might result in many other individuals being exposed. All other cases should be reported within 24 hours. Laboratories should report mpox cases within 24 hours of resulting the specimen through I-NEDSS (either ELR or provider reporting).

For additional information on mpox, visit Information For Healthcare Professionals | Mpox | Poxvirus | CDC. If you need additional assistance, contact your local health department.