Lab guidance updated for Ebola specimens
The following Risk Assessment for Performing Laboratory Testing on Suspected Ebola Cases was issued on Oct. 20 and is based upon recent new or updated web links concerning care for patients under investigation for Ebola virus disease. These include:
Lab Procedures for Ebola Specimens
- Specimen collection
- Specimen transport
- Preparation of specimen for testing
- Centrifugation
- Specimen workup
- BSC decontamination
- Chemistry, coagulation, hematology testing
- Urinalysis
- Malaria testing
- Blood cultures
- Use of automated laboratory instruments
- Specimen disposal
CDC Guidance for Healthcare Providers
Tightened Guidance for U.S. Health Care Workers on Personal Protective Equipment (PPE) for Ebola
Reviewing updated and proven infection control guidance for healthcare workers is demonstrated by personnel safely treating patients with Ebola at Emory University Hospital, Nebraska Medical Center and National Institutes of Health Clinical Center. The guidance provides detailed step-by-step instructions for properly donning and doffing PPE. This enhanced guidance is centered on the following three principles:
- rigorous training, practice and proven competency with PPE utilization;
- ensuring complete skin coverage while wearing PPE; and
- supervision by trained monitors confirming adherence to the standards.
This guidance is similar to MSF’s (Doctors Without Borders) guidance to protect skin and mucous membranes, utilizing meticulous and precise procedures to avoid contamination, using oversight and observers to ensure processes are followed, and disinfection of PPE prior to removal.
Additional information about these updates is available on the CDC website.
Caring for Suspect or Confirmed Patients with Ebola
CDC also provided an outline about what should and should NOT be done for patients under investigation for Ebola virus disease.
Infection Prevention and Control Recommendations for Hospitalized Patients with Known or Suspected Ebola Virus Disease in U.S. hospitals
This document, issued on Oct. 18, discusses key components of standard, contact and droplet precautions recommended for prevention of Ebola transmission in U.S. hospitals such as: patient care equipment; patient care considerations; aerosol generating procedures; hand hygiene, environmental infection control; safe injection practices; duration of infection control precautions; monitoring and management of potentially exposed personnel; and monitoring, management and training of visitors.
Ebola Virus Disease Information for Clinicians in U.S. Health Care Settings
On Oct. 15, the CDC issued an update on clinical presentation and clinical course, pathogenesis, laboratory findings, initial evaluation of patients known or suspected to have Ebola treatment and vaccines.
Safe Management of Patients with Ebola Virus Disease in U.S. Hospitals
Also on Oct. 15, the CDC provided answers to frequently asked questions, including:
- Are U.S. hospitals ready to care for patients with Ebola virus disease?
- What should U.S. hospitals do if they have a patient with suspect Ebola?
- When should patients with suspected Ebola in U.S. hospitals be tested?
- Why do responders in Africa wear so much personal protective equipment (that can include full body suits) for this Ebola outbreak when CDC says hospitals here could safely manage the care of an Ebola patient without a full body suit?
Interim Guidance for Specimen Collection, Transport, Testing, and Submission for Persons Under Investigation for Ebola Virus Disease in the United States.
Besides CDC guidance and updates, personnel at Emory University on Oct. 6 released Ebola Preparedness Protocol draft guidance and the American Society for Microbiology provided Interim Laboratory Guidelines for Handling/Testing Specimens, both of which can be used as resources to aid in decision-making.
When determining what actions or procedures to incorporate into your laboratory, it is important to determine ahead of time what measures should be in place to safely protect staff while providing care for the patient. This would be the time to perform a risk assessment to identify all potential sources of hazardous exposure and identify steps or procedures to mitigate such risks.
Develop a preparedness plan, standardize protocols for PPE usage and train appropriately, and identify minimal diagnostic testing procedures in order to make a diagnosis. Specific questions to consider are:
- When is testing required?
- What testing should be performed?
- Who should perform the testing and under what safety conditions?
- What types of specimens should be collected?
These issues should be discussed and implemented in advance with your professional and laboratory staff.
General Considerations:
- Limit initial testing of patients to rule in/out Ebola or other hemorrhagic fever virus (HFV) diagnosis. Additional testing may be determined upon consultation with infectious diseases and microbiology staff. Any referral testing from suspect patients should be discussed with the referral laboratory prior to submitting specimens.
- All specimens taken from the patient may be labeled as “SUSPECTED HFV.”
- See the table below for detailed description of testing that may be considered after consultation.
- Testing that requires specimen removal from patient’s room and transport of samples to laboratory should be kept to a minimum. (Do not use a pneumatic tube system.)
- Specimen processing may be performed in the patient’s room, nearby in a contained testing area, inside a biological safety cabinet (BSC) located in a negative pressure room (e.g., an acid-fast bacilli or AFB suite), or inside a BSC located in an isolated area of the laboratory. Specimen processing should be performed while wearing appropriate PPE (impermeable gown, double gloves, eye protection, N-95 mask and shoe covers). PPE should not be re-used or leave the testing area. Place all PPE into a double-bag which contains absorbent pads soaked with bleach, then placed in a rigid plastic, impervious container for disposal. (See disposal instructions at the end of this document).
In the analytical phase, it will be important to document testing performed, testing personnel, the methods utilized and the final results.
As the understanding of Ebola evolves, stay up to date with CDC infection control experts.
| Procedure | Hazards | Methods for Control |
|---|---|---|
|
Percutaneous injuries or needlesticks Breakage of the specimen container Care should be taken to avoid contamination of the external surfaces of the container. |
Alert laboratory that specimens are being collected. Place patient under contact and droplet precautions. Adhere to updated PPE guidance. Use plastic vacutainers. Limit the use of sharps. Wipe down all containers with hospital disinfectant. Place specimens in sealed plastic bags and durable, leak-proof secondary containers for transport. Disinfect specimens and container before transport. |
|
Breakage of the specimen container. |
Hand-carry all specimens to the laboratory in a clearly labeled, durable, leak-proof secondary container. |
|
|
Preparation of specimen for testing Typical testing ordered for these patients are CBC, chem. panel, Binax NOW rapid malaria test, Ebola PCR, and aerobic and anaerobic blood cultures. |
Aerosolization, splash, or splatter |
Minimize the number of workers handling the specimens. Follow CDC recommended PPE guidance. Perform work inside a certified class II BSC Limit the traffic around the BSC. Perform work over a disinfectant moistened paper towel. Use only pipette tips with barrier filters. Use a dedicated sharps container with added disinfectant. |
Breakage and aerosolization |
If possible, do not centrifuge specimens. If centrifugation is necessary, load and unload sealed centrifugation buckets inside the BSC. |
|
Accidental transfer of contaminated material from the BSC |
Remove and replace gloves after specimen handling. All waste must be discarded and contained inside the BSC. Disinfect all tubes before removing from BSC. Place specimens in sealed plastic bags (new bags). Wipe the outside of the bags with disinfectant. Place specimen bags into a rigid leak-proof container. Wipe outside of container with disinfectant. Remove gloves and dispose inside trash container in the BSC. Don new gloves. Wipe all trash with disinfectant and remove decontaminated items from the BSC in sealed bags or containers. |
|
Contamination of BSC surfaces |
Wipe the inside of the BSC with disinfectant. Remove all PPE and discard into medical waste stream. |
|
Aerosolization, splash, or splatter |
Recommend limiting testing to iSTAT or equivalent point of care (POC) system, performed in the patient's room, particularly for high-risk or known positive patients. | |
Exposure to body fluid |
Urinalysis available as a urine dipstick may be performed in the patient's room or in BSC. |
|
Aerosolization, splash, or splatter |
Collect in a lavender top Ethylenediaminetetraacetic acid (EDTA) blood tube. Perform rapid antigen malaria test (if available) within BSC. Prepare slides inside a BSC. Perform malarial smear testing as outlined by CDC. Wipe underside of slide with disinfectant before removing from BSC. Stain with Giemsa and read as usual. |
|
Aerosolization, splash, or splatter |
Inoculate bottles directly from patient stick using bottle adaptor. Wipe the outside of the bottles with approved disinfectant and place into a rigid, leak-proof container for transport to the blood culture instrument. Load into the blood culture instrument. Positively flagged blood culture bottles should be unloaded from the instrument into a rigid, leak-proof container and transported to the BSC for Gram staining. Prepare slides for Gram-stain examination, and allow to dry. Fix the slide in methanol for 30 minutes, followed by dry heat at 95 degrees Celsius for 1 hour to inactivate the specimen. Wipe underside of slide with disinfectant before removing from BSC to view microscopically. Inside the BSC, inoculate plates as per protocol based on Gram-stain result. Seal the sub-cultured plates with parafilm or shrink seals and place plates in a biohazard bag for incubation. Wipe the outside of the plastic bags with hospital disinfectant. Incubate plates and observe for growth. After notable growth, perform subcultures while working inside the BSC. Proceed with identification of growth from sub-cultured plates. |
|
Aerosolization, splash, or splatter |
Using of automated lab instruments, in the open lab environment increases the risk for aerosolization and potential spread of infection. Methods of instrument decontamination and the work space should be carefully considered and dealt with before utilizing such instruments. |
|
Breakage and aerosolization |
Autoclave all specimens prior to disposal. |
