The Importance of Proper Specimen Collection and Handling
India is between stages 2 and 3 of the COVID 19 pandemic. At this juncture, precautions should be taken while handling the specimens that are suspected or confirmed for COVID 19, in the clinical laboratories to minimize the risk of infection transmission. It involves safety practices followed by laboratory staff during phlebotomy, sample processing, and proper disposal of waste. Timely communication between clinical and laboratory staff is essential when lab investigations are requested for a suspected or confirmed case of COVID 19. Such specimens should be labeled accordingly and the laboratory staff should be alerted to ensure proper specimen handling.
Precautions to be taken while collecting samples from the clinical laboratories:
Other than the molecular diagnostic method for COVID 19 (RT-PCR), many routine investigations are done on the patient’s blood, urine, respiratory fluid, etc. Here I am discussing the precautions to be taken while collecting and processing such samples in the clinical laboratories.
First and foremost all laboratories should perform a site-specific and activity-specific risk assessment to identify and mitigate risks.
Risk assessments and mitigation measures are dependent on:
- The procedures performed
- Identification of the hazards involved in the process and/or procedures
- The competency level of the lab personnel
- The lab equipment and facility
- The resources available
Routine diagnostic testing of specimens can be handled in a BSL – 2 laboratories using standard precautions. All the clinical laboratories are BSL-2.
{Table below depicts the different biosafety level laboratories [WHO, 12.02.2020]}
A variety of specimens are received for testing in the clinical laboratories. Different samples contain different concentrations of COVID 19.
The figure below depicts COVID 19 shedding in clinical specimens in confirmed cases
As indicated in the above figure, though less but there is risk of transmission of infection by a blood sample. So laboratory safety plays an important role in containing the virus.
Laboratory Safety:
Following measures to be taken while collecting/processing specimens of suspected/confirmed case of COVID 19 for routine tests.
1. Special considerations during Phlebotomy/Sample collection
- Patients should maintain social distancing of a minimum of 1 meter while waiting for phlebotomy and should wear a mask.
- Phlebotomist should wear appropriate PPE (Mask, gloves, gown/apron, goggles/face shield)
- Reuse of tourniquets can spread COVID. So disposable tourniquets should be used
- Sanitise phlebotomy chairs after every use
- Decontaminate phlebotomy room
2. Special considerations during sample processing within the laboratory
- Use of appropriate PPE by lab technicians while processing the specimens.
- After receiving the samples in the laboratory, the external disinfection of containers should be carried using 1% sodium hypochlorite solution.
- Use of autoanalyzer for testing without opening of cap of sample containers wherever possible. E.g., Haematological tests like CBC, HB, etc.
- Biochemical tests, microbiological tests, blood smear preparation, respiratory, and fluid cytology specimens which need opening of sample containers, should be opened in a validated biosafety cabinet.
- Avoid splash, agitation, or leakage of samples while centrifuging. After centrifugation open the tubes in level 2 biosafety cabinet.
- After running COVID 19 suspected/confirmed samples in the machine, run 2 tubes of 1% sodium hypochlorite solution. This takes care of machine decontamination.
- After completion of processing, the sample tubes and PPE are autoclaved followed by incineration.
- Decontaminate work surfaces and equipments with appropriate disinfectant (for example hypochlorite, alcohol, hydrogen peroxide, quaternary ammonium compounds, and phenolic compounds).
Lab waste management:
Handle lab waste from suspected/confirmed COVID 19 patient specimens as all other biohazardous waste in the laboratory. Currently, there is no evidence to suggest that this laboratory waste needs any additional packaging or disinfection procedures.
