Guidance for U.S. Hospitals and Clinical Laboratories on Performing Routine Diagnostic Testing for Patients with Suspected Marburg Virus Disease*
* see Background for definition of Marburg virus disease
This document provides guidance for hospitals and clinical laboratories on performing routine diagnostic (non-marburgvirus) testing necessary for management and care of patients with suspected marburgvirus infection, while minimizing risk to laboratory personnel.
Ill travelers returning from areas currently experiencing an outbreak of Marburg virus disease (MVD) are more likely to have febrile infections other than MVD, particularly if they do not report an epidemiologic risk factor within 21 days prior to symptom onset. Patients with symptoms should be tested and treated accordingly for other more likely conditions. Clinical laboratories can safely perform common diagnostic testing by following Standard Precautions for All Patient Care and the Bloodborne Pathogen Standard (29 CFR 1910.1030).
Clinicians with concerns about MVD in a patient should contact their jurisdictional health department immediately (via 24-hour Epi-On-Call contact list) and follow jurisdictional protocols for patient assessment. Clinical teams should coordinate with public health officials and CDC to assess the risk of MVD based on the clinical presentation and epidemiologic risk factors to determine if marburgvirus testing is needed, and if other causes of illness should be considered (e.g., malaria). Timely identification of other more likely pathogens and access to routine laboratory testing, such as blood counts and chemistries, is essential for providing appropriate patient care.
CDC’s Viral Special Pathogens Branch (VSPB) is available 24/7 to public health departments for consultations on MVD or other viral hemorrhagic fevers by calling the CDC Emergency Operations Center at 770-488-7100 and requesting VSPB’s on-call epidemiologist.
- For the purpose of this guidance, a suspect case of MVD refers to a patient who is referred for marburgvirus testing after consultation with CDC or their jurisdictional health department (24-hour Epi-On-Call contact list) because they are determined to have:
- A thorough travel history and screening should be collected on every ill person presenting for healthcare. Hospitals with concerns about a patient with compatible symptoms and potential epidemiologic risk factors should contact their jurisdictional health department (24-hour Epi-On-Call contact list) or CDC as soon as possible for consultation to determine if marburgvirus testing is indicated. These patients should be isolated at a healthcare facility, in a private room, and continue to undergo appropriate clinical assessment and management while health officials determine whether marburgvirus testing is indicated. Prior travel to a MVD-affected region should not be a reason to defer diagnostic testing needed for patient care.
- If it is determined that a patient meets the criteria for marburgvirus testing, the patient is considered a suspect case of MVD and should be managed under isolation precautions until receiving a negative marburgvirus test result on a sample collected > 72 hours after the patient first developed symptoms. Routine testing to monitor the patient’s clinical status and diagnostic testing for other potential causes of the patient’s illness should be pursued while marburgvirus testing is underway. Clinical laboratories can safely perform common diagnostic testing by following Standard Precautions for All Patient Care and the Bloodborne Pathogen Standard (29 CFR 1910.1030). If a hospital facility is unable to provide appropriate clinical care and laboratory diagnostic testing for a suspect case of MVD, the patient should be transferred to a facility that is able to provide appropriate management until marburgvirus testing is completed.
- Marburgvirus testing should only be performed after consultation with public health officials. Following consultation with local/state health departments and CDC, presumptive testing for marburgviruses is available at select public health laboratories within the Laboratory Response Network(LRN). Refer to Guidance for Collection, Transport and Submission of Specimens for Marburgvirus Testing. Health department staff will facilitate access to testing at the LRN reference laboratories. For additional guidance on packaging and shipping, refer to and consult with the testing facility for additional requirements.
- The United States Occupational Safety and Health Administration (OSHA) developed the Bloodborne Pathogens Standard (29 CFR 1910.1030)to minimize workplace exposure of personnel to bloodborne pathogens. All laboratories that handle patient specimens in the United States must always comply with this standard. CDC considers the risk of laboratory personnel contracting a marburgvirus or other viral causes of hemorrhagic fevers during routine clinical testing to be low if the laboratory adheres to the safety procedures consistent with the Bloodborne Pathogens Standard as well as CDC’s Standard Precautions for All Patient Care.
- Marburgviruses and ebolaviruses are in the same virus family Filoviridae and are closely related. Guidance for ebolaviruses can be applied to marburgviruses.
Marburgviruses are bloodborne pathogens that can spread through blood or body fluids of infected people and cannot be transmitted through air, water, or food. Following the Bloodborne Pathogens Standard and Standard Precautions for All Patient Care, particularly the guidance to prevent sharps and needlestick injuries, has shown to effectively prevent laboratory acquired illnesses from bloodborne pathogens, such as a marburgvirus.
MVD is a rare and often deadly disease in humans. MVD can be confused with more common causes of febrile illness like malaria, influenza, COVID-19, typhoid fever, meningococcemia, and other bacterial and viral infections. Additionally, patients with a marburgvirus infection may present with concurrent infections (e.g., co-infection with malaria). Responsible patient care requires hospitals and laboratories to evaluate patients for other causes of illness, whether or not marburgvirus testing is indicated. Routine laboratory testing to monitor the patient’s clinical status and diagnostic testing for other potential causes of the patient’s illness should be pursued while marburgvirus testing is underway.
It is important for clinicians and laboratory professionals to provide comprehensive care for patients with suspected marburgvirus infection. They can safely and effectively perform other diagnostic testing on clinical specimens from these patients by following Standard Precautions for All Patient Care and the Bloodborne Pathogen Standard (29 CFR 1910.1030). If a patient is determined to meet criteria for marburgvirus testing, the patient is considered a suspect case of MVD and should be managed under isolation precautions until receiving a negative marburgvirus test result on a specimen collected >72 hours after symptom onset. If a hospital facility is unable to provide appropriate clinical care and laboratory/diagnostic testing for a suspect case of MVD, the patient should be transferred to a facility that is able to provide appropriate management until marburgvirus testing is completed.
If a patient is not determined to meet criteria for marburgvirus testing outlined above, or is referred for marburgvirus testing and tests negative for marburgviruses on a specimen collected > 72 hours after the patient first developed symptoms, the patient subsequently should be managed under Standard Precautions and continue to receive appropriate diagnostic testing and care.
Healthcare facilities should conduct thorough travel history and screening of all patients. If MVD is a concern, the patient(s) should be promptly isolated according to CDC’s guidance for emergency departments and the jurisdictional health department (24-hour Epi-On-Call contact list) should be consulted to determine if the patient should be referred for marburgvirus testing.
The following routine clinical laboratory tests are critical to assist clinicians in evaluating an ill traveler.
- Complete blood count (CBC), including differential and platelet count
- Sodium, potassium, bicarbonate, blood urea nitrogen, creatinine, and glucose concentrations
- Liver function tests
- Coagulation testing, specifically prothrombin time (PT), expressed as an international normalized ratio (INR)
- Chemical urinalysis (dipstick)
- Blood culture for bacterial pathogens. The early initiation of blood cultures may be important, even if the patient will be transported prior to culture results, as blood cultures may be an essential component of the ultimate diagnosis.
Based on clinical evaluation, diagnostic testing for other common causes of acute febrile illness in returning travelers may be indicated, including malaria and common causes of respiratory and gastrointestinal illnesses. If warranted based on presenting symptoms, consider use of multiplex PCR panels that detect common respiratory or gastrointestinal pathogens in addition to evaluation for the following:
CDC recommends immediate blood smears with same-day results for malaria testing. If timely blood smears are not available, a rapid diagnostic test (RDT) can be done initially while processing a blood smear with pre-treatment blood (prior to treatment with antimalarials) to confirm the results of the RDT and to determine the percent of infected red cells and species of malaria. Facilities that do not have the expertise or CLIA certificate to perform definitive malaria testing on site should contact their state health department to facilitate the definitive diagnosis. CDC and state health departments can assist with providing a timely diagnosis of malaria. See the Guidance for Malaria Diagnosis in Patients with Suspect Ebolavirus Infection in the United States and Malaria Diagnosis & Treatment in the United States for more information.
Respiratory viruses such as SARS-CoV-2, Influenza, and RSV
If COVID-19 is suspected, refer to Testing to find information on testing for SARS-CoV-2 with nucleic acid amplification tests and antigen tests, as well as specific guidance for point-of-care testing and self-testing.
Consider testing for influenza during periods of high prevalence. Refer to Information for Clinicians on Influenza Virus Testing | CDC and Rapid Diagnostic Testing for Influenza: Information for Clinical Laboratory Directors | CDC.
Consider testing for respiratory syncytial virus (RSV) during RSV season, particularly with infants, young children, older adults, and adults with chronic medical conditions. Refer to For Healthcare Professionals: RSV (Respiratory Syncytial Virus) | CDC.
All laboratory personnel who collect, handle, or test human specimens must comply with the OSHA Bloodborne Pathogens Standard (29 CFR § 1910.1030). In addition, laboratory staff should perform site- and activity-specific risk assessments before beginning testing. Performing a laboratory risk assessment helps to identify:
- The hazards associated with working with an infectious or potentially infectious agent
- The likelihood of a person’s exposure to that agent
- The consequences of such an exposure to personnel
These risk assessments should evaluate the specimen’s path throughout the laboratory as well as all work processes to identify potential exposure risks. The results of the risk assessment should be documented in an Exposure Control Plan, as required by the Bloodborne Pathogens Standard (29 CFR § 1910.1030), that includes engineering controls, administrative controls (including work practices), and appropriate personal protective equipment (PPE) to mitigate the identified risks.
The following areas should be considered priority items to focus on during a clinical laboratory site- and activity-specific risk assessment.
- Specimen management and transport, including the path of the specimen through the laboratory, particularly avoiding transport through high-traffic areas and pneumatic tube systems
- Use of any needles or other sharps, including glass, and their disposal
- Potential for splashing, spraying, spattering, or generation of droplets
- Equipment hazards (e.g., the potential for creating aerosols, sprays, splashes of the specimen while testing and using equipment)
- Biosafety cabinet (BSC) certification, operation, and safe work practices
- Decontamination procedures, including spill response, and methods for surface decontamination and, if necessary, decontamination of equipment
- Infectious waste management
- Engineering controls and safety equipment
- Administrative controls (e.g., communication protocols, entry and exit procedures, personnel training and competency, medical surveillance, exposure response)
- PPE selection and use, including donning and doffing procedures
For additional information on conducting a risk assessment, see Biological Risk Assessment: General Considerations for Laboratories.
Laboratory workers may use a variety of PPE to prevent transmission of infectious pathogens to staff during the collection, processing, and testing of patient specimens. Laboratory staff must be trained in the proper use of PPE, including donning and doffing. Proper use of PPE is critical for worker safety, and strict adherence to protocols is essential.
PPE to be used during specimen collection
Refer to the following guidance for more information on the proper PPE to be used during specimen collection.
- Guidance on Personal Protective Equipment (PPE) To Be Used By Healthcare Workers during Management of Patients with Confirmed Ebola or Persons under Investigation (PUIs) for Ebola who are Clinically Unstable or Have Bleeding, Vomiting, or Diarrhea in U.S. Healthcare Settings, Including Procedures for Donning and Doffing PPE
- For U.S. Healthcare Settings: Donning and Doffing Personal Protective Equipment (PPE) for Evaluating Persons Under Investigation (PUIs) for Ebola Who Are Clinically Stable and Do Not Have Bleeding, Vomiting, or Diarrhea
PPE to be used when performing laboratory testing
All staff involved in collection, handling, and management of clinical specimens from patients with suspected marburgvirus infection should be notified of the nature of the specimen to ensure that the specimens are handled appropriately following the Bloodborne Pathogen Standard. When manipulating clinical specimens from patients with suspected marburgvirus infection, staff should use a combination of engineering controls, work practices, and PPE to protect their mouth, nose, eyes, and bare skin from coming into contact with patient specimens. For example:
- Proper PPE
- Disposable gloves
- Solid-front wrap-around gowns that are fluid-resistant or fluid-impermeable
- Surgical mask to cover all of nose and mouth
- Eye protection such as a full-face shield or goggles/safety glasses with side shields
- Manufacturer-installed safety features for instruments that reduce the likelihood of exposure
- A Class II biosafety cabinet (BSC) should be used for specimen manipulation (e.g., opening a tube, preparing an aliquot)
- Staff should use a secondary container when transporting specimens within and outside of the laboratory
If clinical laboratories decide to require supplementary PPE beyond what is recommended above, this may necessitate additional steps (e.g., staff must be fit tested and medically cleared to wear an N95®respirator). These facilities must provide additional training and have staff practice procedures using the PPE before using them in the laboratory. Using unfamiliar equipment or PPE without sufficient training and practice may lead to unsafe practices and increases the risk of exposure, especially when removing PPE. Consistently following specific PPE procedures is essential to protect personnel. Periodic review of donning and doffing processes with staff at regular intervals is strongly recommended.
When determining what laboratory equipment is appropriate for use with specimens from patients with suspected MVD, laboratories should consider several factors.
- In general, the risk of transmission of marburgvirus in a clinical laboratory is similar to the risk or transmission of other bloodborne pathogens, including HIV, Hepatitis B, and Hepatitis C.
- Laboratories should consider using equipment with closed tube systems in which the specimen container (e.g., vacutainer tube) stays capped during testing.
- Centrifugation poses a risk of aerosolization. If centrifugation is necessary for testing, centrifuges should have sealed buckets or sealed rotors. The rotors and buckets should be loaded in a BSC. After centrifugation, open the sealed buckets or rotors inside a BSC or enclosed hood.
- Blood culture instruments (automated and benchtop) have been used successfully after careful evaluation through a risk assessment. Subculture of any positive blood culture bottles (whether from automated, benchtop, or manual procedures) should be performed within a BSC.
Marburgviruses are enveloped viruses — the easiest type of virus to inactivate — and are readily inactivated by standard chemical decontamination procedures used in laboratories and hospitals. When disinfectants damage their lipid envelope and/or denature proteins, the virus is no longer infectious. EPA’s List L (EPA’s Disinfectants for Use Against Ebola Virus, which is also effective for marburgviruses) and List Q (EPA’s Disinfectants for Emerging Viral Pathogens) identify disinfectants that inactive marburgviruses.
1. Cleaning and Disinfecting of Testing Surfaces
Decontamination of marburgviruses can easily be performed on laboratory surfaces and the outside of instrument surfaces using EPA List L: Disinfectants for Use Against Ebola Virus products that are compatible with instrumentation. However, not every instrument surface will be compatible since some of the products on List L are sodium hypochlorite-based (i.e., bleach) and can be corrosive if used in high concentrations. In addition, enveloped viruses can be inactivated with solutions on EPA List Q: Disinfectants for Emerging Viral Pathogens, which includes isopropyl alcohol.
2. Instrument Use and Decontamination for Non-marburgvirus Testing
In general, laboratory instruments can be maintained as they normally would with any other bloodborne pathogen, and as recommended in the Bloodborne Pathogen Standard. In November 2022, CDC spoke with several of the largest U.S. manufacturers of routine diagnostic instruments. The manufacturers indicated that following the Bloodborne Pathogen Standard should ensure safe use of their instruments for all testing, including for high-risk patients and specimens. The manufacturers also reiterated that most of their blood testing instruments are closed systems that do not require any decontamination between patient specimens. However, laboratories should consult the manufacturers’ instructions, or the manufacturer directly, on whether there is a need and how to decontaminate the interior surfaces or areas of their specific laboratory instruments. CDC can help laboratories speak directly to instrument manufacturers about decontamination or warranty coverage by contacting DLS@cdc.gov.
3. Handling Spills
The basic principles for blood or other potentially infectious material spill management are outlined in the OSHA Bloodborne Pathogens Standard and the CDC Biosafety in Microbiological and Biomedical Laboratories [PDF – 438 pages]. Points to consider are:
- If the spill creates aerosols, evacuate staff until the aerosols have had time to settle.
- Limit the number of personnel involved in the clean-up.
- Develop protocols for safely remediating spills containing broken glass. Do not handle broken glass or other sharps directly.
- Before any spill clean-up is initiated, ensure staff are trained and wear PPE as identified in the site-specific risk assessment to protect against direct skin and mucous membrane exposure of cleaning chemicals, contamination, and splashes. PPE use must be in accordance with the OSHA PPE (29 CFR 1910.132) and Respiratory Protection (29 CFR 1910.134) standards. PPE should include, at a minimum:
- Disposable gloves
- Solid-front wrap-around gowns that are fluid-resistant or fluid-impermeable
- NIOSH Approved® particulate respirator equipped with an N95 filter or greater or surgical mask
- Eye protection such as a full-face shield or goggles/safety glasses with side shields
- Shoe covers if the spill is large and there is a splash area to avoid tracking potentially infectious material away from the spill area.
- When cleaning up a spill, look for areas of splashes away from the main spill and clean the spill working from the outside of the spill radius inwards.
- For small spills, absorbent material wetted with disinfectant can be used to clean the area. Be sure to allow for the appropriate amount of contact time.
- For larger spills, cover the spill with absorbent material and douse the area with disinfectant. It may be necessary to increase the concentration of the disinfectant used to offset the dilution factor caused by the volume of the spilled material and/or increase contact time.
- All materials used for cleanup must be treated as infectious and disposed of in a biohazard waste container. Any sharps should be placed into a sharps container.
Managing waste from a MVD patient should be handled and disposed of as a Category A agent. For information about procedures and regulations regarding waste associated with the care of MVD patients, refer to CDC’s Waste Management Guidance, DOT’s Planning Guidance for Handling Category A Solid Waste, DOT’s Managing Solid Waste Contaminated with a Category A Infectious Substance, and your local or state jurisdictional regulations.
Specimens collected from patients with suspect MVD are not select agents. Clinical specimens that have been confirmed to contain infectious marburgvirus by viral isolation are classified as select agents. CDC will work with the facility to determine proper reporting and handling of specimens from these patients.
Waste generated during the handling and testing of specimens from patients with suspect or confirmed MVD is not subject to Federal Select Agent regulations (42 CFR § 73.3(d)(1)) unless viable marburgvirus is intentionally isolated from that waste.
Additional Note: N95® and NIOSH Approved® are registered certification marks of the U.S. Department of Health and Human Services (HHS).