Guidance for U.S. Laboratories for Managing and Testing Routine Clinical Specimens When There is a Concern About Ebola Virus Disease
On This Page
- Clinical Laboratory Testing of Clinical Specimens when Ebola Virus Disease is a Concern
- Compliance with Occupational Safety and Health Administration (OSHA) Bloodborne Pathogens Standard
- Risk Assessment and Mitigation
- Laboratory Equipment
- Point of Care (POC) Testing
- Transporting Patient Specimens within the Facility
Who this is for: Laboratory and other healthcare personnel handling and testing routine clinical specimens when concern about Ebola virus disease (EVD) has been raised by a physician.
What this is for: To provide updated guidance for management and evaluation of routine clinical specimens for differential testing and diagnoses other than EVD.
How to use: This guidance should be use as a supplement to CDC's Guidance for Collection, Transport and Submission of Specimens for Ebola Virus Testing in the United States.
Due to a heightened concern in the United States about Ebola, this document provides guidance for clinical laboratories on testing needed for the assessment and care of patients for which Ebola Virus Disease (EVD) is a concern, while minimizing risk to laboratory personnel.
This document updates and replaces the previously posted document: How U.S. Laboratories Can Safely Manage Specimens from Persons Under Investigation for Ebola Virus Disease.
Clinicians should maintain a high index of suspicion and consult their local and state health departments and CDC when ill travelers from Ebola-affected countries are identified; it is important to recognize that the likelihood of EVD even among symptomatic travelers returning from these countries is very low. In the hospital setting, where policies and procedures should be in place to safeguard health care workers, consideration of Ebola should not delay diagnostic assessments, laboratory testing, and appropriate care for other, more likely medical conditions1.This guidance is based on input received from numerous hospital and laboratory directors, infectious disease physicians, CDC Ebola response teams, and state health officials.
- CDC recommends that Ebola testing be conducted only for persons who meet the criteria for persons under investigation (PUIs) for EVD: A person who has both consistent signs or symptoms and risk factors as follows:
- Elevated body temperature or subjective fever or symptoms, including severe headache, fatigue, muscle pain, vomiting, diarrhea, abdominal pain, or unexplained hemorrhage; AND
- An epidemiological risk factor within the 21 days before the onset of symptoms.
- If there is a clinical suspicion of Ebola, a determination whether a patient is, or is not a PUI should be made in consultation with public health officials as quickly as possible in order to ensure that patient care is not compromised. The period of time between when a clinical suspicion for Ebola is raised to the time a PUI determination is made can vary. Clinical laboratories, especially those in Ebola Assessment and Ebola Treatment Hospitals, should be prepared to provide a timely and minimum menu of testing to ensure that medical evaluation is not delayed for any patient; in the U.S., most of these persons will not have EVD, but have had another etiology for their illness1. Timely identification of these other etiologies is essential to appropriate patient care.
- Presumptive testing for Ebola virus is available at 52 LRN laboratories located throughout the United States. Hospitals should follow their state and/or local health department procedures for notifying and consulting about Ebola virus testing requests before contacting CDC.
- Any presumptive positive Ebola test result must be confirmed at the CDC to inform public health decisions. For guidance on confirmatory Ebola virus testing, refer to Guidance for Collection, Transport and Submission of Specimens for Ebola Virus Testing in the United States.
- If a hospital chooses to use a commercial Ebola virus test, specimens should also be submitted to an LRN facility or CDC for definitive Ebola virus testing2, 3.
- To minimize risk to personnel, a risk assessment must be performed by the laboratory director, safety officer, and other responsible persons to determine the potential for exposure from sprays, splashes, or aerosols generated during all laboratory processes, procedures, and activities. Risks should be mitigated by implementing engineering controls, administrative and work practice controls, and use of appropriate personal protective equipment (PPE).
- To date, CDC considers the risk of acquiring EVD or other viral hemorrhagic diseases through laboratory testing to be low, but not zero risk. (See Interim U.S. Guidance for Monitoring and Movement of Persons with Potential Ebola Virus Exposure). Some recommended measures to minimize the risk of laboratory transmission when testing patient specimens include: limiting the number of staff engaged in testing, evaluating and segregating equipment used for testing, and performing testing in a dedicated space.
- The decision to perform testing in a hospital care laboratory using existing instrumentation, or alternatively, acquiring dedicated point of care (POC) instrumentation should be carefully evaluated. Considerations may include whether Ebola patient testing may lead to core laboratory instrumentation being removed from service, and the planning should include how to mitigate such potential outcomes.
- The United States Occupational Safety and Health Administration (OSHA) Bloodborne Pathogens Standard (29 CFR 1910.1030) was developed to reduce the potential exposure of personnel to blood borne pathogens. All U.S. laboratories handling patient specimens are required to comply with this standard at all times; strict adherence is an initial step in providing protection to personnel.
- U.S. hospitals or clinical laboratories concerned about a patient with potential Ebola virus exposure should contact their local and/or state health departments and CDC (770-488-7100).
Ebola virus is transmitted through contact with infected blood or body fluids (e.g., urine, feces, and vomit) from symptomatic persons and with objects such as needles that have been contaminated with infected body fluids. PUIs for EVD should be managed by following appropriate precautions to prevent transmission of Ebola virus to others and contamination of the hospital environment. See CDC’s infection control guidance.
In consultation with public health authorities, states are identifying hospitals which are capable of assessing persons that meet the criteria for persons under investigation (PUIs) for EVD. (see Interim Guidance for U.S. Hospital Preparedness for Patients with Possible or Confirmed Ebola Virus Disease: A Framework for a Tiered Approach and Interim Guidance for Preparing Ebola Assessment Hospitals). This document provides information that may be appropriate for all clinical laboratories. The guidance is especially important for Ebola Assessment Hospitals, which are designated facilities that are prepared to receive, isolate, and evaluate a PUI while the need for Ebola testing is assessed. If testing is warranted, these hospitals continue to provide patient care until an Ebola diagnosis can be confirmed or ruled out, and until a discharge or transfer is completed. Most PUIs will be identified through active monitoring of returned travelers, and directed to an Assessment Hospital. It is also possible that persons with unrecognized EVD will present to a Frontline healthcare facility (an acute care hospital or other emergency care setting including urgent care clinic, or critical access hospital) without prior notification; these facilities should be prepared to promptly identify and isolate these patients according to the CDC’s guidance for emergency departments. Frontline healthcare facilities are not expected to provide prolonged care (>12–24 hours) for a severely ill patient. It is important to remember that due to the potential stigma associated with EVD, patients returning from affected countries may be reluctant to disclose their travel history.
CDC recommends that Ebola testing be conducted only for persons who meet the criteria for PUIs and have compatible clinical syndromes. If there is a clinical suspicion of Ebola, a PUI determination and medical evaluation should be made as quickly as possible in order to ensure patient care is not compromised. Most PUIs have had other etiologies for their illness such as malaria, influenza and other respiratory illnesses, typhoid fever, and other bacterial or viral infections1. Clinical laboratories should be prepared to provide sufficient testing to ensure patient care is not compromised while patients undergo assessment. The clinician should determine specific testing according to the patient presentation and travel history.
- U.S. hospitals or clinical laboratories concerned about a patient with potential Ebola virus exposure should contact their relevant local and state public health authorities. In joint consultation with CDC (770-488-7100), these agencies will assist in determining whether criteria for a PUI are met and appropriate measures for monitoring the patient will be determined in consultation with the attending health care provider.
- The decision to test for Ebola should not be made without consultation with public health officials. CDC should be notified immediately if a decision is made to test. CDC considers a single diagnostic test used in the absence of a confirmatory diagnostic algorithm insufficient for public health decision-making. If a hospital chooses to use a commercial Ebola virus test, specimens should also be submitted concurrently to an LRN facility or CDC for definitive Ebola virus testing2, 3.
CDC and state health department laboratories are available to assist hospitals in the selection, interpretation, and sourcing of additional laboratory tests needed to manage PUIs.
Since clinically indicated laboratory testing and clinical decision-making for evaluating Persons Under Investigation (PUIs) may be variable, Ebola Assessment Hospitals must be capable of providing timely results for the following laboratory tests:
- A complete blood count (CBC), including differential, and platelet count (For information on automated CBCs, see “Laboratory Equipment” section of this document.)
- Sodium, potassium, bicarbonate, blood urea nitrogen, creatinine, and glucose concentrations
- Liver function tests
- Coagulation testing, specifically prothrombin time (PT), expressed as international normalized ratio (INR)
- Urinalysis (dipstick)
- Blood culture for bacterial pathogens (For information on automated or manual blood cultures, see “Laboratory Equipment” section of this document.)
- Malaria testing (smear or rapid testing or PCR)*
- Influenza virus testing during periods when influenza prevalence is high**
Ebola Treatment Centers should be able to provide the above tests, as well as additional testing required to manage a patient with EVD.
*Immediate blood smears with same-day results are recommended for malaria testing. If rapid diagnostic testing or PCR is performed, a blood smear with pre-treatment blood should also be processed to determine the percent of red cells infected. 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 the state health departments can assist with providing a diagnosis of malaria in a timely fashion. More information can be found at CDC’s malaria website and https://www.cdc.gov/dpdx/malaria/index.html.
**Negative results when using point of care rapid influenza diagnostics on respiratory specimens from older children and adults do not exclude infection because of their lower sensitivity compared with molecular assays. It may also be beneficial to ascertain infection with non-influenza respiratory viruses when testing respiratory specimens from patients with febrile respiratory illness. Molecular assays for numerous respiratory viruses including both influenza and non-influenza viruses are often available as multiplex assays and may aid in diagnosis of common respiratory infections. See https://www.cdc.gov/flu/professionals/diagnosis/rapidlab.htm for more information on rapid influenza diagnostic tests.
All laboratory personnel who collect, handle, or test human specimens must comply with the United States Occupational Safety and Health Administration (OSHA) Bloodborne Pathogens Standard (29 CFR § 1910.1030)4. Performance of site-specific risk assessments should consider the path of the sample throughout the laboratory, including all work processes, procedures and tasks to identify potential exposure risks and to mitigate these risks by implementing engineering controls, administrative controls (including work practices), and appropriate PPE. This is a well-recognized standard that was developed to protect laboratory personnel from exposure. U.S. hospitals have safely managed patients with viral hemorrhagic fevers (VHF), even when the diagnosis of VHF was only made after patient discharge5, 6, 7, 8, 9.
Laboratory risk assessment is a process used to identify: 1) the hazards associated with a known or potentially infectious agent and the activities being conducted with them; 2) the likelihood of a person’s exposure to that agent or material; and 3) the consequences of such an exposure to personnel or equipment (e.g., a laboratory acquired infection or the need to take a machine off-line for extended periods)10.
A risk assessment of all processes, procedures, and activities in the laboratory must be performed to determine the potential for exposure to the specimen through generation of aerosols, sprays, splashes, or spills. Based on the assessment, a plan to mitigate the identified risks should be implemented using engineering controls, administrative controls (including work practices), and use of appropriate PPE (see section below).
CDC is aware of hospitals that have safely used instruments in their core laboratories to test specimens when EVD is a concern, however, following risk assessment, laboratories may choose to use point of care testing or other alternative procedures to minimize disruption to the core laboratory and minimize risk to laboratory personnel.
Some items for clinical laboratories to focus on during their site-specific risk assessment should include:
- Specimen management and transport, including the path of the sample through the laboratory particularly avoiding transport through high-traffic areas or pneumatic tube systems
- Equipment hazards (e.g., the potential for creating aerosols, sprays, splashes of the specimen when performing testing and using equipment)
- Biological Safety Cabinet certification, operation and safe work practices
- Decontamination procedures, including spill response, and methods for decontamination of equipment
- Infectious waste management
- Laboratory design
- Laboratories that have open room designs should also consider the risk of exposure to workers present in the area but that are not directly involved with testing of a particular sample
- Some recommended measures to minimize the risk of laboratory transmission when testing patient specimens include: limiting the number of staff engaged in testing, evaluating and segregating equipment used for testing, and performing testing in a dedicated space
- Engineering controls and safety equipment
- Laboratory communication protocols
- Laboratory entry and exit procedures
- PPE selection and use
- Facility ventilation and filtration
- Employee medical surveillance and exposure response
- Safe sharps handling
- Personnel safety training and competencies
Additional information on conducting a risk assessment can be found in the CLSI Document M29-A4 “Protection of Laboratory Workers from Occupationally Acquired Infections; Approved Guideline-Fourth Edition”11.
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.
Appropriate PPE should be based on a risk assessment of the situation, the work being done, as well as the capabilities of the user. Too much PPE can be just as hazardous as too little, resulting in limited visibility, mobility and potential heat stress issues; ill-fitting PPE can cause distraction and reduced sensory perception.
- PPE must be provided to the employees free of cost by the employer as required by the OSHA bloodborne pathogens standard
- PPE must prevent blood or other potentially infectious materials from passing through and reaching the employee’s work clothes, street clothes, undergarments, skin, eyes, mouth, or other mucous membranes
- Each laboratory should work with its institution’s infection control and laboratory safety departments to ensure laboratory personnel safety
- PPE selected must not be compromised by chemicals used in laboratory procedures
- Consideration may be given to using a buddy system to ensure that safe donning and doffing procedures are followed
- Consultation with CDC is available to assist laboratories with selecting appropriate PPE (770-488-7100)
Laboratory staff must be trained in the proper donning and doffing of PPE. The proper donning and doffing of PPE is critical for worker safety, and strict adherence to protocols is essential.
1. PPE to be used during specimen collection
Healthcare personnel including laboratory staff that collect patient specimens from a confirmed patient or a PUI exhibiting obvious bleeding, vomiting or diarrhea or who is clinically unstable and/or will require invasive or aerosol-generating procedures should wear the PPE described in the hospital guidance.
Healthcare personnel caring for a PUI who is clinically stable and does not have bleeding, vomiting or diarrhea can wear the alternate ensemble described in the ED guidance and on the Assessment hospital page.
2. PPE to be used when performing laboratory testing
It is strongly recommended to work inside a certified Class I or certified Class II biosafety cabinet (BSC) when handling or manipulating patient specimens. When all proper procedures are strictly followed, a Class I BSC will protect the worker, and a Class II BSC will protect the worker and the sample from contamination.
When manipulating clinical specimens when EVD is a concern, 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, including:
- Proper use of a certified Class I or Class II biosafety cabinet AND
- 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
Clinical laboratories may decide to include additional PPE that may necessitate additional requirements, (i.e., staff must be fit tested and medically cleared to wear an N-95 respirator). The facility must provide additional training and have staff practice these procedures using the PPE before using them in the workplace. Using unfamiliar equipment or PPE without sufficient training and practice may lead to inadvertent breaches in safe practices and may increase a person’s risk of contaminating his or her clothes, mouth, or eyes, especially when removing PPE. Consistency of these planned procedures is essential to protect personnel.
Some laboratory equipment used for routine testing may not be appropriate for testing specimens from PUIs because: (a) The equipment may generate an aerosol or (b) recommended disinfectants to inactivate Ebola virus may affect the performance of the instrument or void the manufacturer’s warranty. CDC and FDA are currently working with manufacturers to assess and resolve the safety issues of laboratory equipment for testing specimens from PUIs.
Some considerations regarding use of laboratory equipment are:
- Laboratories should consider using equipment with closed tube systems in which the specimen container (e.g., vacutainer tube) stays capped during testing.
- Centrifugation can pose a risk of aerosolization. If centrifugation is necessary for testing, centrifuges should have sealed buckets or sealed rotors. After centrifugation, the sealed buckets or rotors should be opened inside a biosafety cabinet.
- Automated blood culture instruments have been used in the core lab after careful evaluation of the risk assessment, ensuring that the outside of the bottle is cleaned with a disinfectant labeled for non-enveloped viruses before putting it in the instrument, and ensuring that staff who handle the bottles are wearing gloves. Alternatively, benchtop blood culture instruments are available, or blood culture bottles may be incubated manually in separate incubators and monitored for turbidity as an indication of growth. Subculture of any positive blood culture bottles should be performed within a biosafety cabinet in a separate laboratory area segregated from the core lab, preferably by using commercially available “venting unit” devices that sheath the needle during extraction of blood from the bottle to prevent needlesticks.
- Automated hematology analyzers with a closed tube system have been used in the core lab after careful evaluation of the risk assessment, ensuring that the outside of the tube is cleaned with a disinfectant labeled for non-enveloped viruses before running the sample on the instrument, and ensuring that staff who handle the specimens are wearing risk assessment-defined PPE. Alternatively, benchtop moderate complexity closed tube hematology analyzers are also available for laboratories electing to perform laboratory testing in a POC location.
If POC instruments are used, the clinical laboratory director must ensure they meet their intended use, as approved by the Food and Drug Administration (FDA). This information is specified in the “Intended Use” section of the Product Insert.
- If the intended use of the instrument excludes testing of critically ill patients:
- Then use of the POC instrument for testing critically ill patients is considered off-label use. Before reporting patient results, the laboratory must establish the performance specifications for accuracy, precision, sensitivity, specificity, reportable range of test results, reference intervals and any other performance characteristic required for test performance in a critically ill patient population. Validation must be performed prior to use for testing patient specimens.
- In addition to establishing performance specifications for the specific use of the test, the laboratory must also comply with the relevant provisions of the CLIA regulations (42 CFR Part 493) and document performance of quality control and proficiency testing, and that relevant laboratory education/experience qualifications are met by laboratory directors and testing personnel.
- It is recommended to place point of care (POC) instruments within an enclosure or behind a barrier to contain any splashes or potential aerosols that may be generated.
- If placed inside a BSC, ensure that appropriate airflow is not compromised by overloading the inside of the BSC, or by blocking the front or back air intake grilles. Consideration should be given to verifying inward airflow at the front opening of the BSC while instruments are operating.
- When a BSC is not available or possible, then additional safety equipment should be used to contain any splashes or potential aerosols generated. This could be a small benchtop BSC, a PCR workstation (e.g., “dead air box”), a plexiglass splash shield, or other physical containment device.
- If clinical laboratories decide to add POC instruments specifically for testing specimens from PUIs, staff should be trained and should practice these procedures in advance while wearing the appropriate PPE.
NOTE: See Appendix 1 for questions to consider when selecting instruments and for a list of instruments identified by institutions that have cared for patients with EVD. This list does not indicate an endorsement of the product nor should this be considered a complete list of all test instruments that may be acceptable.
- Primary specimen containers should only be handled with proper PPE, including gloves.
- Before removing patient specimens from the site of care, it is advisable to plan the route of the sample from the bedside to the laboratory or testing area in order to avoid high-traffic areas.
- Before removing patient specimens from the site of care, the outside of the specimen containers should be decontaminated with an approved disinfectant as described in Interim Guidance for Environmental Infection Control in Hospitals for Ebola Virus.
Note: Recommended disinfectants are those known to kill non-enveloped viruses and can be found in List L of Disinfectants for Use Against the Ebola Virus. This list of registered disinfectants meets the CDC’s criteria for use against the Ebola virus on hard, non-porous surfaces.
- In compliance with 29 CFR §1910.1030, specimens should be placed in a durable, leak-proof secondary container.
- After placement in a secondary container, specimens should be hand-carried to the laboratory. DO NOT use any pneumatic tube system (automated or vacuum specimen delivery system) for transporting specimens.
Ebola virus is classified as a Category A infectious substance by the Department of Transportation (DOT). Specimens from PUIs or patients confirmed to have Ebola virus infection should be packaged and shipped as Category A infectious substances. For guidance on packaging and shipping, refer to Guidance for Collection, Transport and Submission of Samples for Ebola Virus Testing in the United States and the DOT Hazardous Materials Regulations (HMR).
As noted above, recommended disinfectants are those known to kill non-enveloped viruses and can be found in List L of Disinfectants for Use Against the Ebola Virus. These disinfectants should be used for cleaning and disinfecting of testing surfaces, handling spills, and cleaning and decontamination of laboratory equipment.
1. Cleaning and Disinfecting of Testing Surfaces
See the Interim Guidance for Environmental Infection Control in Hospitals for Ebola Virus for recommendations regarding the cleaning and disinfection of patient care area surfaces including the management of blood and body fluid spills. These recommendations also apply to cleaning and disinfecting in a laboratory where specimens are being processed from PUIs or patients with confirmed EVD.
2. Handling Spills
The basic principles for blood or body substance spill management are outlined in the OSHA Bloodborne Pathogens Standard2. CDC guidelines recommend removal of bulk spill material, cleaning the site, and then disinfecting the site with a disinfectant effective against the potential agent. Points to consider are:
- Limit the number of personnel involved in the clean-up
- Develop protocols for safely remediating spills containing broken glass
- Before any spill clean-up is initiated, ensure staff are trained and wear recommended PPE to protect against direct skin and mucous membrane exposure of cleaning chemicals, contamination, and splashes, including, at a minimum:
- Disposable gloves
- Solid-front wrap- around gowns that are fluid-resistant or fluid-impermeable
- N-95 rated respirator (staff must be fit tested and medically cleared), or surgical mask to cover all of nose and mouth
- Eye protection such as a full face shield or goggles/safety glasses with side shields
- All materials used for cleanup must be treated as infectious and disposed of in a biohazard waste container
3. Decontamination of Equipment
- For decontamination of laboratory instruments and equipment, use of an EPA-registered hospital disinfectant with label claims for non-enveloped viruses (e.g., norovirus, rotavirus, adenovirus, and poliovirus) for cleaning and decontaminating surfaces or objects is recommended.
- The laboratory should consult in advance with the manufacturer to ensure the most appropriate selection of such disinfectants and their use on the equipment. Some disinfectants can be detrimental (i.e., corrosive) to the instrument’s surface.
- The Operator’s Manual should be consulted to see what the manufacturer recommends when taking the equipment out of commission or preparing for maintenance or repairs. CDC is aware of the challenges laboratory workers and their institutions face when these instructions are not provided in the manuals and is in consultation with FDA and the manufacturers to resolve these issues.
If an instrument is contaminated during use and there is no procedure for decontamination of the internal compartments without compromising the instrument operability, then the instrument may need to be removed from service as there are no other validated methods for ensuring that any remaining viral particles are no longer viable.
- Ebola virus is classified as a Category A infectious substance by the Department of Transportation (DOT) and, when transported in commerce, is regulated by DOT’s Hazardous Materials Regulations (HMR, 49 C.F.R., Parts 171-180). Any item transported in commerce that is contaminated or suspected of being contaminated with a Category A infectious substance must be packaged and transported in accordance with the HMR. This includes untreated patient specimens from PUIs, medical equipment, sharps, linens, and used health care products (such as soiled absorbent pads or dressings, kidney-shaped emesis pans, portable toilets, used PPE (e.g. gowns, masks, gloves, goggles, face shields, respirators, booties, etc.), or byproducts of cleaning.
- For solid waste generated during laboratory testing, OSHA Bloodborne Pathogen Standard (29 CFR § 1910.1030) specifies that:
- Potentially infectious materials shall be placed in a primary container which prevents leakage during collection, handling, processing, storage, transport, or shipping
- The primary container shall be placed within a second container which is puncture-resistant and prevents leakage during handling, processing, storage, transport, or shipping
- If available and proper procedures are strictly adhered to, steam sterilization (autoclaving) as a waste treatment process will inactivate the virus. If used, there are numerous requirements that must be followed for the safe and effective operation of autoclaves. After waste from PUIs or confirmed for EVD has been autoclaved, it can be combined with the laboratory waste stream as regulated (non-class A) medical waste.
- If an autoclave is not available in the facility, other arrangements must be made with a licensed external waste contractor to transport, treat, and dispose of the waste. Permits are required and other restrictions may apply based on state or local regulations.
- The regulations associated with disposal of biohazards are complex, and vary by state and local requirements. Check with your state’s medical waste management program for more guidance on solid and liquid waste.
- Waste generated during the handling and testing of specimens from PUIs or patients with confirmed EVD is not subject to Federal Select Agent regulations (42 CFR § 73.3(d)(1)), UNLESS viable Ebola virus is intentionally isolated from that waste.
As outlined in the Interim Guidance Regarding Compliance with Select Agent Regulations for Laboratories Handling Patient Specimens that are Known or Suspected to Contain Ebola Virus13, specimens from PUIs are not select agents. Patient specimens that have been proven to contain infectious Ebola virus by viral isolation may be classified as select agents. CDC will work with the facility to determine proper reporting and handling of specimens from these patients.
A. Selecting Laboratory Equipment
Clinical laboratories need to be prepared to test clinical specimens to support patient care when EVD is a concern. Below are suggested questions to facilitate decision making regarding selecting or using laboratory instruments to test these specimens.
- Is the specimen contained within a closed chamber and does it remain contained within a closed chamber throughout testing?
- Even if the specimen remains contained within a closed chamber, has an evaluation been performed to determine if the manufacturer’s safety features are effective in protecting instrument operators from exposure to aerosols or sprays from patient specimens?
- If the specimen container is opened during testing, have the potential routes of exposure to the operator during sample preparation and testing been identified, and have engineering controls and/or PPE been implemented?
- Does the instrument employ wash and decontamination solutions in its test system to adequately inactivate bloodborne pathogens, including Ebola virus?
- Does the manufacturer provide hazard warnings and PPE guidance with their troubleshooting instructions?
- Have the potential exposure routes associated with handling and transport of the instrument’s on-board waste collection been identified and PPE evaluated and implemented?
- How close is the instrument to other operations in the laboratory?
- Are there instructions for cleaning and decontaminating the instrument, including track systems?
- Do recommended disinfectants meet the EPA requirements for inactivating non-enveloped viruses?
For POC instruments under consideration for use in isolation areas, refer to questions 1-8 above in addition to the following:
- What are the size and operational requirements of the entire test system? Consider the instrument’s environmental operating requirements including temperature and humidity, and proper reagent storage (e.g., refrigerator or freezer).
- Does the “Intended Use” statement of the device labeling allow for testing critically ill patients? (FDA has not approved the use of some devices for testing critically ill patients.)
- If the instrument is placed inside a BSC, will it compromise the proper BSC operation and protective functions (e.g., air flow)?
- Is the instrument difficult to operate while wearing required PPE?
- Is the instrument easily decontaminated?
Laboratory equipment used by some laboratories testing Ebola virus-positive specimens
Some U.S. hospitals have treated patients who tested positive for Ebola virus. The following table lists instruments these hospitals selected to conduct clinical laboratory testing on these patients. The conditions under which hospital laboratories used these instruments varied; some chose to place these instruments in a biosafety cabinet, whereas others operated them under BSL 2 or BSL 3 conditions14, 15.
Note: POC testing instruments placed inside a biosafety cabinet (BSC) may interfere with the BSC airflow and compromise staff safety. Care should be taken not to overload the BSC with equipment, and consideration should be given to verifying inward airflow at the front opening of the BSC while instruments inside are operating.
The following is a list generated from institutions other than CDC. This list is for information only and is not intended as a CDC endorsement of these instruments or practices, nor should this be considered a complete list of all test instruments that may be acceptable.
|ITC||Hemochron Signature Elite|
|F. Hoffman-La Roche||CoaguChek|
|Blood Culture||Plastic bottles/manual monitoring method|
|Malaria||Smear fixed in methanol for 15 mins
|Ebola virus testing||Biofire FilmArray*|
*If used, this test result is presumptive only and must be confirmed at CDC.
- Karwowski et al. Clinical Inquiries Regarding Ebola Virus Disease Received by CDC — United States, July 9–November 15, 2014. MMWR Morb Mortal Wkly Rep. December 5, 2014. 63(Early Release);1-5) Available at URL: https://www.cdc.gov/mmwr/preview/mmwrhtml/mm63e1205a1.htm?s_cid=mm63e1205a1_w
- 2014 FDA Ebola Virus Emergency Use Authorizations
- http://www.aphl.org/aphlprograms/preparedness-and-response/Documents/APHL-Guidance-for-Clinical-Laboratories-Using-FDA-Authorized-Assays-for-Ebola.pdf [PDF – 5 pages]
- United States Occupational Safety and Health Administration (OSHA) Bloodborne Pathogens Standard (29 CFR 1910.1030). Available at URL: https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=10051&p_table=STANDARDS
- Amorosa V, et al. Imported Lassa fever—Pennsylvania, USA, 2010. Emerg Infect Dis. 2010 Oct; 16(10):1598-600. Available at URL: http://wwwnc.cdc.gov/eid/article/16/10/10-0774_article
- Imported case of Marburg hemorrhagic fever – Colorado, 2008. Centers for Disease Control and Prevention (CDC). MMWR Morb Mortal Wkly Rep. 2009 Dec 18; 58(49):1377-81. Available at URL: https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5849a2.htm
- Timen A, et. al., Response to imported case of Marburg hemorrhagic fever, in the Netherlands. Emerg Infect Dis. 2009 Aug; 15(8):1171-5. Available at URL: http://wwwnc.cdc.gov/eid/article/15/8/09-0015_article
- Centers for Disease Control and Prevention (CDC). Imported Lassa fever—New Jersey, 2004. MMWR Morb Mortal Wkly Rep. 2004 Oct 1;53(38):894-7. Available at URL: https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5338a2.htm
- Centers for Disease Control and Prevention (CDC). Interim guidance for managing patients with suspected viral hemorrhagic fever in U.S. hospitals. MMWR Morb Mortal Wkly Rep. 2005 May 19. Available at URL: https://www.cdc.gov/HAI/pdfs/bbp/VHFinterimGuidance05_19_05.pdf [PDF – 4 pages]
- U.S. Dep’t. Health Human Services, Centers for Disease Control and Prevention, and National Institutes of Health. Biosafety in microbiological and biomedical laboratories (BMBL). 5th ed. Washington, DC: US Government Printing Office; 2009. Available from URL: https://www.cdc.gov/biosafety/publications/bmbl5/BMBL.pdf [PDF – 438 pages]
- Clinical and Laboratory Standards Institute (CLSI). Protection of Laboratory Workers from Occupationally Acquired Infections; Approved Guideline-Fourth Edition. CLSI Document M29-A4. Wayne, PA: Clinical and Laboratory Standards Institute; 2014. http://clsi.org/
- Guidance on Personal Protective Equipment To Be Used by Healthcare Workers During Management of Patients with Ebola Virus Disease in U.S. Hospitals, Including Procedures for Putting On (Donning) and Removing (Doffing). Centers for Disease Control and Prevention website. Updated October 20, 2014. Available at URL: https://www.cdc.gov/vhf/ebola/healthcare-us/ppe/guidance.html
- Interim Guidance Regarding Compliance with Select Agent Regulations for Laboratories Handling Patient Specimens that are Known or Suspected to Contain Ebola Virus. US Centers for Disease Control and Prevention website. Updated November 19, 2014. Available at URL: https://www.cdc.gov/vhf/ebola/healthcare-us/laboratories/select-agent-regulations.html
- P.C. Iwen, et al. 2014. An Integrated Approach to Laboratory Testing for Patients with Ebola Virus Disease. Lab Med. 45(4): e146-e151.
- C.E. Hill, et al. 2014. Laboratory Test Support for Ebola Patients Within a High-Containment Facility. Lab Med. 45(3):e109-e111.
Additional references which may be of interest are:
- Clinical and Laboratory Standards Institute (CLSI). “Clinical Laboratory Safety; Approved Guideline—Third Edition”. CLSI document GP17-A3. Wayne, PA: USA. CLSI; 2012.
- “Guidelines for Safe Work Practices in Human and Animal Medical Diagnostic Laboratories”, MMWR, January 6, 2012 / 61(01); 1-101 https://www.cdc.gov/mmwr/preview/mmwrhtml/su6101a1.htm
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- Page last updated: October 8, 2015
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