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4. Biosafety Guidelines for the Clinical Laboratory

It is of the utmost importance that proper biosafety guidelines are followed by clinical laboratories when handling samples from suspected COVID-19 patients. The IFCC TF on COVID-19 recently published recommendations for biosafety measures for preventing infection from COVID-19 in clinical laboratories accessible at the following link. Key summary recommendations are listed below:

How can biosafety measures be implemented in clinical chemistry laboratories during the COVID-19 pandemic?

1a. Laboratories should adopt social distancing measures within the workplace as much as possible and feasible.

1b. The potential exposure and health status of the laboratory personnel is monitored daily.

What personal hygiene and personal protective equipment (PPE) should be used in clinical chemistry laboratories during the COVID-19 pandemic?

2a. Laboratory professionals must adhere rigorously to universally recommended standard precautions (i.e. frequent hand washing for at least 40 s with soap and water, or hand sanitizer when there is no access to handwashing, and to avoid touching the face) to minimize the risk of exposure to the virus.

2b. Laboratory professionals must wear standard laboratory PPE (i.e. masks and gloves, laboratory coat or gown, and eye protection) at all times.

2c. Laboratory professionals should wear preferably an N95 mask while engaged in aerosol-generating procedures on all non-centrifuged samples potentially containing vital SARS-CoV-2 particles.

How should laboratory staff handle routine patient specimens during the COVID-19 pandemic?

3a. For routine testing of blood, urine and body fluids, laboratories should use automated instruments and analyzers with closed preanalytical robotics, where possible.

3b. When manually handling non-respiratory specimens, aerosol-generating non-centrifuged sample processing steps should be carried out in a BSL2 cabinet, wearing the recommended PPE.

3c. The specimens should be sealed immediately after testing. High-risk specimens should be promptly disinfected or autoclaved.

3d. If there are no accidents, wait for more than 10 min for further processing after centrifugation stops. When the specimen suspected of COVID-19 is centrifuged, the operator must not leave the centrifuge. If an accident is suspected, or in some way the centrifugation is abnormal, stop the centrifugation. After replacing the biosafety level 3 protection equipment, stop centrifugation for more than 30 min, carefully open the lid, and spray and sterilize with 75% ethanol or other disinfectants. Take out the centrifuge rotor with blood collection tubes and then put them in the biosafety cabinet to treat.

How should staff decontaminate laboratory equipment and surfaces during the COVID-19 pandemic?

4a. Laboratory staff should decontaminate working surfaces with standard disinfectants approved for SARS-CoV-2 infections. The frequency shall be decided on local basis according to the volume of work, but shall not be basically less frequent than every 3 h.

4b. If a sample positive for SARS-CoV-2 is suspected of being leaked or contaminates the biosafety cabinet and bench and causes limited pollution: use a disinfectant with an effective chlorine content of 5500 mg/L for disinfection for more than 30 min; the disinfectant must be prepared immediately and used within 24 h. If positive specimens cause laboratory contamination: keep the laboratory space closed to prevent access by unauthorized personnel and to prevent the spread of pollutants. Cover the contaminated area with a towel containing 5500 mg/L of effective chlorine disinfectant and disinfect for more than 30 min. Peracetic acid (2 g/m3) or other disinfectants (3% H2O2, 100 mg/L chlorine dioxide, etc.) can be used to fumigate the laboratory overnight or disinfectant aerosol can be sprayed for 1–2 h.

In addition, interim guidelines from the World Health Organization on laboratory biosafety guidance related to coronavirus disease were updated on March 19th, 2020.

Click here for a full list of WHO suggested decontaminants and here for a full list of EPA suggested decontaminants.

Efficacy of Masking: The efficacy and necessity of surgical grade or N95 masks in the clinical laboratory and the general public has not been well defined. In a recent paper in Nature Medicine by Leung and colleagues, surgical face masks were shown to significantly reduce the detection of influenza virus RNA in respiratory droplets and coronavirus RNA in aerosols, with a trend toward reduced detection of coronavirus RNA in respiratory droplets. In light of increasing evidence towards the efficacy of masking, the WHO has reversed its initial recommendation and now supports government initiatives that require or encourage the public wearing of masks, marking a major shift. The CDC has also encouraged general masking, highlighting the importance of masking for all healthcare workers whether patient-facing or not.

COVID-19 Detection in Different Clinical Specimens: An important consideration in biosafety is the detectability of COVID-19 in clinical specimens. A recent JAMA article investigated biodistribution among different clinical specimens of inpatients with COVID-19. Study findings are summarized below:

COVID-19 Detection in Domestic Animals: A recent publication in Science investigated the susceptibility of domestic animals, including dogs, cats, chickens, pigs, and ducks. Their findings demonstrated that cats are susceptible to airborne infection while COVID-19 replicates poorly in dogs, pigs, chickens, and dogs. Healthcare workers should keep this in mind when interacting with domestic pets.

 

Additional biosafety resources/publications from other associations include:

 
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