Guidance

Monkeypox: diagnostic testing

Information on taking, submitting and processing samples which potentially contain monkeypox virus.

Applies to England

This guidance is aimed at healthcare workers and clinical diagnostic laboratories both in the public and private sectors.

Monkeypox diagnostic testing is available in UKHSA laboratories and some NHS laboratories. Where these services are available these should be accessed according to local guidance; otherwise monkeypox diagnostic testing service can be accessed through the following guidance.

Information is available on the monkeypox case definitions, and will continue to be updated. There is also information available on the classification of contacts of monkeypox cases and advice for vaccination and follow-up.

Infections such as chickenpox, HSV, molluscum contagiosum and syphilis are all still circulating. Diagnostic testing for these infections should be undertaken as usual, with testing for monkeypox proceeding in parallel if deemed necessary.

Suspected cases

In the first instance, suspected cases must be discussed with local infection clinicians (infectious diseases, microbiology, virology or genitourinary medicine as appropriate). Make sure that the request form indicates the risk factors and the reason that monkeypox is suspected.

Personal protective equipment (PPE)

The minimum recommended PPE for healthcare workers who need to be within 1 metre of a suspected case of monkeypox is droplet and contact precautions, with eye protection where there is a possibility of splash (for example taking diagnostic tests such as throat swab or deroofing lesions) as outlined in the NHSE national infection prevention and control manual.

The national infection prevention and control manual also outlines the minimum recommended level of PPE for inpatient care.

Sampling for diagnostic testing

Monkeypox is diagnosed by PCR test on a viral swab taken from one or more vesicles or ulcers. Swabs should be sent in viral transport media.

Follow the instructions below:

1. Ensure that you are wearing the minimum appropriate PPE as above.

2. Take a single viral swab in viral culture medium or viral transport medium (for example Virocult®) from an open sore or from the surface of a vesicle. If other wounds are present, ensure that the sample is definitely taken from a vesicle, an ulcer or a crusted vesicle. Rub the swab over the lesion and place the swab in the viral culture tube or viral transport medium. Throat swabs are also suitable samples if there are pharyngeal lesions, atypical lesions, or if the patient is a contact of a confirmed case with a possible prodrome syndrome but without a typical rash. Label the tube with the patient’s name and date of birth, the date and site of the sample. Note that unlabelled tubes cannot be processed. Do not send any other sample type unless you have been requested to do so by RIPL clinicians.

3. For high risk contacts of a confirmed or highly probable case who have developed systemic symptoms but do not have a rash or lesions for sampling, you should take a throat swab in viral transport media. Note that even if the throat swab is negative, the individual must continue with monitoring and isolation as instructed,instructed by health protection, and should be reassessed and sampled if further symptoms develop.

4. Samples for investigation of other infections, including sexually transmitted infections, should be packaged separately, with separate request forms.

5. Samples should be sent to your normal local laboratory for forwarding to the Rare and Imported Pathogens Laboratory (RIPL) (for monkeypox testing) and for local processing (all other tests).

6. Samples from suspected cases of monkeypox should be sent by Category B transport.

Sampling for monitoring confirmed or highly probable cases

If follow-up testing is required from a confirmed or highly probable case, either because of clinical deterioration or forto inform discharge planning,from isolation to an inpatient setting, additional samples should be taken and should include all of the following:

  • a lesion swab and throat swab in viral transport medium
  • a blood sample in an EDTA tube
  • a urine sample in a universal sterile container

These samples are needed to assess clinical status and monitor progress.

Samples from confirmed or highly probable cases of monkeypox should be sent by Category B transport to the High Containment MicrobiologyMicrobiology(HCM) unit at Colindale. SeparatePlease detailscontact the haveHCM beenunit providedahead to HCID units to arrange this testing; other Infectious Disease units which require virological monitoring of patientssending shouldany contactsamples High Containment Microbiology at Colindale to arrange this testing.

Submitting diagnostic samples for testing

1. Download and complete the monkeypox testing request form. If you require urgent reporting of results, please ensure that you provide a direct line contact number for the physician designated to receive results, which may be out of hours. If you are requesting that results are emailed, please provide a relevant NHS email address. Results can only be sent to an NHS.net address.

2. Make sure your local microbiology team are aware that the sample is being sent and know which clinician to contact in the event of a positive result.

3. Package the samples carefully following the guidance on page 17 of the RIPL user manual. You must ensure that stoppers and lids are firmly attached, the tubes are labelled with the sample type (for example swab left palm, penile lesion), patient name and date of birth. Do not use an internal study number. Samples that have leaked in transit cannot be processed if there is insufficient material left.processed.

4. Send the samples to your normal local laboratory. Any additional samples for sexually transmitted infections should be packaged separately. Inform your local laboratory that the samples for monkeypox testing should be forwarded for testing. This should be through a licensed Category B courier to:

Rare and Imported Pathogens Laboratory
UKHSA
Manor Farm Road
Porton Down
Salisbury SP4 0JG

DX 6930400, Salisbury 92 SP

The working hours contact for RIPL is 01980 612 348 from 9am to 5pm on weekdays. You can also email ripl@phe.gov.ukripl@ukhsa.gov.uk but do not include patient identifiable information.

Please note that monitoring samples from confirmed cases should not be sent to RIPL. Please contact Colindale HCM to arrange testing for those patients.

5. Samples arriving in the laboratory by 9am8am Monday to Saturday will usually be processed the same day. Positive results will be reported the following day. Samples arriving after 9am8am will be processed the next day. Please contact the laboratory if you require the results to be provided urgently. Routine samples arriving after 9am8am on Saturdays will be processed the following Monday. If urgent testing is required over the weekend, this must be discussed and agreed with the on-call Imported Fever Service consultant (0844 778 8990).

Test results

1. Positive results will be phoned to the designated clinicians: ensure you provide the relevant contact number for this clinician when submitting the specimen. All results will be sent to the referring laboratory through the standard electronic reporting system.

2. The RIPL office can answer results enquiries during opening hours. If chasing a sample, ensure your courier has been contacted first to ensure that receipt of the samples has occurred. If the sample has been sent correctly via a Category B courier, the courier should be able to confirm delivery time.

Information for laboratories handling samples potentially containing monkeypox virus

Monkeypox is a Hazard Group (HG) 3 pathogen. Under normal circumstances, any procedure with HG3 pathogens involving potentially infectious material, where there is a risk of generating aerosols, droplets or splashes, must be performed within an MSC at CL3. However, some diagnostic samples may be handled at CL2 subject to local risk assessment. The following table provides the minimum containment level for handling samples suspected or confirmed to contain monkeypox.

Specimen type / test Suspect/probable/possible case ConfirmedConfirmed/highly probable case
Nucleic acid extraction for the molecular detection of monkeypox virus MSC I, II or III at CL3 until after virus inactivation. (Samples are currently being sent to UKHSA RIPL but other regional centres are likely to be testing in the future) MSC I, II or III at CL3 until after virus inactivation. (These samples are currently sent to Colindale)
Sample transport Transported via Category B route Transported via Category B route
Nucleic acid extraction of skin lesion swabs for molecular assays of infections other than monkeypox virus (for example herpes simplex virus or syphilis) MSC I, II or III at CL2 until after virus inactivation MSC I, II or III at CL3 until after virus inactivation
Respiratory samples MSC I, II or III at CL2 MSC I, II or III at CL2
Other microbiological samples where manual manipulation is required for example plating of culture swabs, urine antigen testing, manipulation of blood cultures or urine MSC I, II or III at CL2 MSC I, II or III at CL3
Routine laboratory blood tests Autoanalysers at CL2 Autoanalysers at CL2
Waste disposal Standard protocols for disinfection and waste disposal Standard protocols for disinfection and waste disposal
Routine blood tests outside of an autoanalyzer Open bench at CL2 with PPE (gloves, laboratory coat +/- eye protection subject to risk assessment)

Samples must be centrifuged using sealed centrifuge rotors or sample cups which are loaded and unloaded in a MSC
Open bench at CL2 with PPE (gloves, laboratory coat +/- eye protection subject to risk assessment)

Samples must be centrifuged using sealed centrifuge rotors or sample cups which are loaded and unloaded in aan MSC
Point of care / near patient testing of lesion swabs Generally, not to be performed but is possible with a local risk assessment which identifies correct PPE to protect the healthcare worker Generally, not to be performed but is possible with a local risk assessment which identifies correct PPE to protect the healthcare worker
Point of care / near patient testing of respiratory samples Should not be analysed unless a local risk assessment has been completed and shows that it can be undertaken safely. Near-patient tests for viral nucleic acid amplification vary widely in their general safety and where aerosols or droplets may be generated. If a local risk assessment can show that any aerosol or droplet generation occurs within a closed analyser, and external surfaces can be cleaned with detergent-based disinfectant, then these tests may be used Not to be performed
Point of care tests / near patient testing of other samples, for example blood gases May be used subject to local risk assessment regarding the potential for the generation of splashes and droplets, and the appropriate use of PPE and disinfection May be used subject to local risk assessment regarding the potential for the generation of splashes and droplets, and the appropriate use of PPE and disinfection

Laboratory exposure may occur via needlestick injury, direct specimen contact, or inhalation of aerosols. These exposures can be avoided if standard biosafety precautions are taken.

It is important that other diagnostic testing is not delayed while waiting for the results of monkeypox testing so as not to delay diagnosis of other illness that may require urgent treatment.

Other procedures, such as extraction or procedures which may generate aerosols, should be performed in a CL3 facility with staff wearing cuffed, back-fastening gowns, gloves and goggles.

For PCR testing of specimens from suspected monkeypox cases (for example testing for syphilis or HSV), the specimens should be opened in an appropriate microbiological safety cabinet in a CL2 facility.

Samples can be inactivated before extraction by heating for 1 hour at 60°C in a validated water-bath or block designed to ensure even heat distribution throughout standard specimen tubes.

Guanidine/guanidinium buffers such as AVL can also be used but work best with additional non-denaturing surfactants (see Inactivation of orthopoxvirus for diagnostic PCR analysis by Vinner and Fomsgaard, and PAHO/WHO guidance).

Inactivated samples can be handled safely with standard laboratory precautions.

Samples from confirmed and highly probable monkeypox cases should be labelled appropriately so that laboratories can ensure that they are handled correctly with the necessary additional precautions as outlined above.

For routine testing of blood samples from suspected or confirmed monkeypox cases (for example for biochemistry, haematology), standard clinical laboratory precautions can be followed, but aerosol generating procedures should be avoided. The risk of infection from these samples is less than that for hepatitis B or any other similar disease.

Surfaces should be decontaminated with standard disinfectants. Waste should be autoclaved and disposed of as per standard laboratory procedures.

Guidance for laboratories seeking to establish monkeypox diagnostic testing capability

UKHSA provides a diagnostic testing service free of charge to NHS users for public health purposes.

UKHSA does not restrict NHS or private laboratories from establishing their own monkeypox testing service, but any such service would be provided at their own expense.

Laboratories planning on establishing local diagnostic testing should ensure they remain compliant with relevant legislation, perform appropriate risk assessments, and assure ongoing quality. Laboratories should be aware that monkeypox is schedule V restricted by the Anti-terrorism, Crime and Security Act 2001.

Laboratories should also ensure that their testing provision is able to maintain compliance with the different operational definitions of HCID for monkeypox within their testing pathways, including the ability to distinguish or escalate for confirmation cases that may be classified as an HCID.

UKHSA does not approve, endorse or recommend a specific commercial monkeypox diagnostic test, although a monkeypox-specific nucleic acid amplification test is recommended, and use of an orthopox-only test is discouraged.

At present, only nucleic acid amplification tests (typically PCR-based) are recommended for provision of testing services. Other test types are available on the market, however their performance characteristics in this outbreak are uncertain and are not recommended by UKHSA.

A list of tests on the commercial market is maintained by FIND.

To ensure confidence and compliance with the current notifiable diseases regulation laboratories it is recommended that UK laboratories follow this process prior to commencing with a monkeypox testing service.

1. Submit a copy of their nucleic acid assay verification file and reporting criteria for peer review to the UKHSA monkeypox Diagnostics cell (contact details below), along with intended go live date and predicted capacity.

2. Technical specialists at Porton Down will provide a peer review that assay selection is reasonable for the service offered and remove the need for confirmatory testing of positive samples by RIPL. This peer review is not an assay approval and laboratories should ensure they follow their standard local assay approval processes including through relevant accredited bodies.

3. Laboratories that have undergone satisfactory peer review are not required to submit samples to UKHSA Porton Down for confirmation.

4. Samples for sequencing will be required and UKHSA will arrange couriers for this if existing courier routes aren’t in place. Minimally it is recommended that positive samples from women, children, patients with overseas travel history and/or treated with anti-viral medicines (such as tecoviramet) are retained for sequencing.

5. Laboratory should work with their UKHSA regional laboratory surveillance Second Generation Surveillance System (SGSS) leads to ensure data feeds from their laboratory systems are reporting correctly to SGSS data system.

6. For monitoring purposes, laboratories should provide both monkeypox negative and positive results into SGSS.

7. It is critical that data collection and reporting systems are in place and tested with monkeypox Data analytics teams before the service goes live to ensure this feeds into the national surveillance programme.

8. A turnaround time within 24 hours from sample receipt, and preferably same day, is desired.

If a laboratory intends to provide testing using an alternative testing methodology please contact the UKHSA monkeypox Diagnostics cell (contact details below) to discuss prior to offering a service as this may have significant implications for public health monitoring purposes.

UKHSA Porton Down may be able to supply control material to assist in assay verification activities (contact through the UKHSA monkeypox Diagnostics cell, see below). A monkeypox External Quality Assurance (EQA) exercise delivered through National External Quality Assessment Services (NEQAS) is planned so submission of assay verification data can help ensure laboratories are considered for participation in that EQA exercise when it becomes available.

UKHSA monkeypox Diagnostics cell contact details: NICC68.Diagnostics@ukhsa.gov.uk This email address should not be used for clinical diagnostic testing enquiries.



Published 24 May 2022
Last updated 211 JulyAugust 2022 + show all updates
  1. Amended in line with the introduction of highly probable case definition and to include information for laboratories seeking to establish monkeypox diagnostic testing capability.

  2. Removed information about clinical helpline.

  3. Updated information on transport of samples from confirmed cases and information on when samples will be processed.

  4. Added link to monkeypox testing request form.

  5. Updated sections on sampling for diagnostic testing, submitting diagnostic samples for testing, test results and information for laboratories handling samples.

  6. Removed the request for blood and urine samples and throat swabs to be submitted for diagnostic testing.

  7. Added information about contacting the monkeypox clinical helpline.

  8. Updated guidance.

  9. First published.