Laboratory Procedures

Routine Chemistry, Hematology, and Urinalysis in Hospitals or Clinical Laboratories

Smallpox vaccine is not recommended for personnel handling and processing routine clinical specimens from monkeypox patients (e.g., urine for urinalysis, blood for CBC, chemistries, microbiology).

Measures should be taken to minimize the risk of laboratory transmission when testing routine clinical specimens from confirmed or suspected monkeypox patients. These may include: limiting the number of staff testing specimens, wearing appropriate personal protective equipment, using rigorously applied standard precautions, and avoiding any procedures that could generate infectious aerosols.

It is recommended that testing for monkeypox be performed in facilities that have recently vaccinated personnel, the necessary equipment, engineering controls, personal protective equipment, and appropriate diagnostic assays available. Diagnostic testing for Orthopoxviruses (which includes monkeypox virus) is available at LRN laboratories located throughout the United States and abroad. There is no commercial assay to detect monkeypox virus.

Hospitals should contact their local or state health departments to inquire about monkeypox virus testing before contacting CDC.

Clinical Pathology, Molecular Testing, and Analysis of Bacterial or Mycotic Cultures

BSL-2 facilities with standard BSL-2 work practices may be used for the following activities:

  • Pathologic examination and processing of formalin-fixed or otherwise inactivated tissues
  • Molecular analysis of extracted nucleic acid preparations
  • Electron microscopic studies with glutaraldehyde-fixed grids
  • Routine examination of bacterial and mycotic cultures
  • Routine staining and microscopic analysis of fixed smears

Manipulating Specimens Suspected to Contain Monkeypox Virus

When possible, successfully vaccinated (i.e., smallpox vaccination within the past 10 years) persons should perform laboratory work that involves handling specimens that may contain monkeypox virus. However, vaccination is not an absolute requirement for handling specimens.

When only non-immunized persons are available, additional personal protection equipment and practices should be used to further reduce the risk for exposures.

Use of a certified Class II Biological Safety Cabinet (BSC) is recommended for manipulations of monkeypox specimens—

  • If a BSC cannot be used, the risk of exposure to an inadvertent sample release should be reduced by the appropriate combinations of personal protective equipment (e.g., respirators, face shields) and physical containment devices (e.g., centrifuge safety cups or sealed rotors).
  • Use sealed centrifuge rotors or sample cups for centrifugation. Ideally, these rotors or cups should be unloaded in a BSC.

For laboratories with personnel vaccinated within the past 10 years—

  • Specimens may be handled in Biosafety Level 2 (BSL-2) facilities, using BSL-2 practices as indicated in the CDC/NIH Biosafety in Microbiological and Biomedical Laboratories, 5th edition (BMBL).
  • Specimen manipulations should be carried out in a certified Class II BSC, especially if there is a potential to generate fine-particulate aerosols (e.g., vortexing or sonication of specimens in an open tube).
  • Directional air flow (negative air pressure with respect to the surrounding area) is recommended, but not required for BSL-2 laboratory facilities.

For laboratories without vaccinated personnel—

  • Routine specimen processing may be handled in BSL-2 facilities, but with more stringent BSL-3 work practices.
  • Laboratory workers must wear protective equipment, including disposable gloves, solid front gowns with cuffed sleeves, and face protection (snugly fitting goggles are preferred; if a face shield is used, it should have crown and chin protection plus wrap around the face to the point of the ear) to provide a barrier to mucosal surface exposure.
  • Centrifugation must be performed using safety cups or sealed rotors. Rotors or safety cups should be opened in a BSC after centrifugation involving monkeypox specimens.

If procedures that generate fine-particle aerosols cannot be contained within a BSC, acceptable methods of respiratory protection include particulate respirators; these respirators provide the minimum level of respiratory protection. Facilities may consider the use of higher levels of respiratory protection, particularly if vaccination status of staff is not confirmed or if personnel cannot be correctly fitted to disposable models. These higher levels may include the use of powered air purifying respirators.

Decontamination of work surfaces after the completion of work or at the end of the day is essential. Any Environmental Protection Agency (EPA)-registered hospital detergent-disinfectant currently used by health-care facilities for environmental sanitation may be used. Manufacturer’s recommendations for use-dilution (i.e., concentration), contact time, and care in handling should be followed.

If the appropriate safety equipment and/or protocols are not available, consideration should be made to refer specimens to a suitably equipped reference laboratory.

Culturing Specimens for Monkeypox Virus

Culture based testing for monkeypox virus should be limited to the CDC.

Disposal of Waste

All cultures, stocks, and other waste containing monkeypox virus should be decontaminated before disposal onsite by using an approved method, such as autoclaving. Materials to be decontaminated outside of the immediate laboratory should be placed in a durable, leak proof container and closed for transport from the laboratory.

Select Agent Regulations

Monkeypox virus identified as belonging to the Central African clade is federally regulated by the final rule “Possession, Use, and Transfer of Select Agents and Toxins” (42 CFR § 73).

Briefly, identification of Central African monkeypox virus in a specimen presented for diagnosis or verification must be: 

  • Reported within 7 calendar days after identification
  • Transferred in accordance with regulations or destroyed on-site by a recognized sterilization or inactivation process if the facility is not registered
  • Secured against theft, loss, or release during the period between identification and transfer or destruction

More detailed information on the identification, possession, use, transfer, and destruction of material containing monkeypox virus can be found on the Federal Select Agent Registry ProgramExternal website.
(Email: lrsat@cdc.gov; Fax: 404.718.2096)

Western African strains of monkeypox virus are not subject to select agent regulations.

Monitoring Healthcare Workers Exposed to Monkeypox Virus

Guidelines for monitoring healthcare workers who have unprotected exposures to patients with monkeypox or laboratory specimens from these patients.

Post-exposure vaccination may be appropriate in cases of direct exposure to monkeypox specimens. Guidelines for the use of smallpox vaccine.