|Year : 2021 | Volume
| Issue : 2 | Page : 108-114
Rolling code on histopathology laboratories during Covid pandemic: A narrative review
Aishwariya Mohanty, Pallavi Mishra, Kailash Chandra Dash, Lipsa Bhuyan, Niva Mahapatra, Abikshyeet Panda
Department of Oral and Maxillofacial Pathology and Oral Microbiology, Kalinga Institute of Dental Sciences, Patia, Bhubaneswar, Odisha, India
|Date of Submission||08-Sep-2020|
|Date of Decision||22-Dec-2020|
|Date of Acceptance||18-Jan-2021|
|Date of Web Publication||17-Apr-2021|
Dr. Pallavi Mishra
Department of Oral and Maxillofacial Pathology and Oral Microbiology, Kalinga Institute of Dental Sciences, Campus-5, Patia, Bhubaneswar, Patia 751024, Odisha.
Source of Support: None, Conflict of Interest: None
Aim: Histopathology laboratories are assigned laboratories where contagious biopsy samples are regularly received for diagnosis and prognosis. SARS-CoV-2 is a new public health crisis that has created a global alarming. As there is a paradigm shift in the work-flow and specimen management during this COVID-19 pandemic, this review article discusses and summarizes proper sterilization protocols that need to be implemented in histopathological laboratories. This write-up highlights the biosafety level requirement along with step-by-step safety protocol from receiving a specimen till reporting of slides by pathologists. Materials and Methods: A literature search was made to review the published recommendation that is applicable for histopathology laboratories in the light of current knowledge and understanding of COVID-19. A humble effort was also made to review the interim guidelines that are updated by the World Health Organization and Center of Disease Control on day-to-day basis and are highlighted in this article. Results: Based on keywords used, 29 relevant articles were found useful and were selected for the review. Conclusion: Of all the precautions, proper hand hygiene practice, use of disinfectants, and personal protective equipment are of utmost importance. Also, several studies have shown that coronavirus was inactivated during routine formalin fixation and tissue processing processes. This article focusses on highlighting the guidelines that could help in anti-spread strategies.
Keywords: COVID-19, histopathology laboratory, nfectious diseases, pandemic, SARS-CoV-2
|How to cite this article:|
Mohanty A, Mishra P, Dash KC, Bhuyan L, Mahapatra N, Panda A. Rolling code on histopathology laboratories during Covid pandemic: A narrative review. J Int Oral Health 2021;13:108-14
|How to cite this URL:|
Mohanty A, Mishra P, Dash KC, Bhuyan L, Mahapatra N, Panda A. Rolling code on histopathology laboratories during Covid pandemic: A narrative review. J Int Oral Health [serial online] 2021 [cited 2022 Aug 17];13:108-14. Available from: https://www.jioh.org/text.asp?2021/13/2/108/313846
| Introduction|| |
Coronaviruses, a positive-strand RNA virus, are an important group of pathogens of birds and mammals. They are spherical in shape with a typical “crown” appearance due to the outer crosslinked glycoprotein helically symmetrical capsid and a pericapsid layer. In the recent past, two coronaviruses, namely, severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS), have caused considerable global illness consternation. Lately, in 2019, a new strain of coronavirus, which was epidemiologically linked to the seafood and wet animal wholesale market in Wuhan, was first reported to the WHO Country Office in China on 31 December 2019. The Coronaviridae Study Group of International Committee on Taxonomy of Viruses named the virus as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the resulting disease as coronavirus disease 2019 (COVID-19). SARS-CoV-2 mainly affects the lining epithelial cells of the respiratory and gastrointestinal tract causing several symptoms like fever, cough, shortness of breath, diarrhea, muscle pain, tiredness, etc. In extremely serious cases, sepsis, septic shock, pneumonia, and acute respiratory distress syndrome could also occur. The patient is usually contagious between 2 and 14 days during which they could develop symptoms. Transmission can occur through respiratory droplets, direct contact, or contaminated surfaces and floors.
COVID-19 has been designated as pandemic on 11th March 2020 by the World Health Organization (WHO) and has encountered the whole world within a short period affecting an enormous segment of humanity. Globally, as of 3:00 pm CEST, 5 August 2020, there have been 18,354,342 confirmed cases of COVID-19, including 696,147 deaths, reported to WHO. SARS-CoV2 is harbored and sheds through respiratory secretions even when the patient may still be asymptomatic. Viruses spread through respiratory droplets, direct or indirect contact with the infected hand, and contaminated surfaces. Some additional form of transmission may be there; hence, all biopsy samples should be treated as potentially harmful, unless confirmed. Histopathology laboratories are assigned laboratories where contagious biopsy samples are regularly received for diagnosis and prognosis. Since infected samples may be submitted to histopathology laboratories for diagnosis, an idea about the route of transmission is very important for the prevention of spread and biosafety maintenance inside the diagnostic laboratories by the healthcare workers.
A humble attempt was made to review the published recommendations as applicable for histopathology laboratories in the light of current knowledge and understanding of COVID-19 using Medical Subject Headings (MeSH) keywords: SARS-CoV-2, COVID-19, Biosafety, Histopathology, and Laboratories. The WHO, Centers for Disease Control and Prevention (CDC), and various professional bodies have also recommended guidelines for infection control in laboratories. As there is a paradigm shift in the work-flow and specimen management that needs to be implemented in the histopathology laboratory, this article focusses and summarizes the suggestions to revise and redesign the working protocols to be implemented in the histopathology laboratory. Healthcare workers must follow the “standard precautions” including principles of social distancing, hand hygiene, respiratory hygiene, wearing PPE (masks, face shield/goggles, full-sleeved water-resistant gowns, laboratory coat, gloves, eye protection, and shoe covers) and refrain from touching mucosal surfaces (eyes, nose, and mouth) while handling COVID-19 samples.
| Materials and Methods|| |
A literature search was made to review the published recommendation that is applicable for histopathology laboratories in the light of current knowledge and understanding of COVID-19. A humble effort was also made to review the interim guidelines that are updated by the World Health Organization and Center of Disease Control on day-to-day basis and are highlighted in this article.
Inclusion criteria were as follows:
- Article with laboratory management during any pandemic.
- Article with laboratory management during SARS-CoV-2.
- Interim guidelines by various bodies for the management of laboratory during coronavirus pandemic.
- WHO safety guidelines during COVID-19 pandemic.
Exclusion criterion was as follows:
- Any article not related to laboratory and coronavirus.
| Results|| |
As this is the latest topic, only a few clinical studies were there, and more studies are yet to be conducted. Based on keywords used, many articles were excluded depending on the initial screening of the title and abstract as they did not qualify the objective of the present review. Finally, 29 relevant articles were found useful and were selected for the review.
| Discussion|| |
Biosafety maintenance while receiving specimen
According to the World Health Organization, all specimens received for laboratory investigation should be considered as potentially contagious; hence, caution must be exercised during each stage of sample processing. Healthcare workers should adequately take standard precautions and biosafety measures while receiving, transporting, and handling specimens, as summarized in this article. The WHO in 2004 recommends Laboratory Biosafety Manual Guidelines for safe handling of pathogenic microorganisms in laboratories. The WHO and Center for Disease Control and Prevention (CDC) are also updating interim guidelines for proper handling of specimens associated with COVID-19.
Healthcare workers should not directly touch the sample container with a bare hand. They should wear gloves, use proper disinfectants, and wash their hand regularly while receiving any clinical/human sample. The SARS-CoV-2 virus can stay active for 24 h on cloth and wood, 48 h on glass, 4 days on stainless steel and plastic, and until 7 days on the outer layer of a medical mask. A study found that the COVID-19 virus survived 4 h on copper, 24 h on cardboard, 48 h on stainless steel, and up to 72 h on plastic. Kampf et al. concluded that the coronavirus could survive up to 5 days on silicon rubber and surgical gloves and 1–2 days on disposable gowns. The virus mutilates on copper surfaces, suggesting its antiviral property. The release of copper ions and the generation of reactive oxygen species inactivate the virus. Coronavirus can persist in a contagious state on an average of up to 9 days. The sequence of the viral genome shows a close resemblance to the human SARS-CoV virus as well as other bat viruses., Hence, researchers proposed that disinfectants used for coronaviruses like SARS and MERS should inactivate SARS-CoV-2 also. There is a great deal of discussion regarding infection and disinfection of inanimate surfaces. Less-porous surfaces like plastic and steel absorb droplets less easily and hence should be disinfected properly. Cervino and co-workers outlined different disinfection methods for different materials. SARS and MERS virus can be inactivated with 62–71% ethanol, 0.5% hydrogen peroxide, or 0.1% sodium hypochlorite within 1 min. But, other biocidal agents such as benzalkonium chloride and chlorhexidine are less effective. A study by Duan et al. revealed that irradiation with ultraviolet light for 60 min on several coronaviruses in a culture medium resulted in undetectable levels of viral infectivity. Household bleach, ethanol (70%), povidone-iodine (7.5%), chloroxylenol (0.05%), chlorhexidine (0.05%), and benzalkonium chloride (0.1%) are also efficient in obtaining not detectable viruses on surfaces. So, enough disinfectant solution should be applied to allow surfaces to remain wet and untouched long enough for the disinfectant to inactivate pathogens, as recommended by the manufacturer. Spraying or fumigating disinfectants to environmental surfaces, in indoor spaces, is not recommended for COVID-19 as it is ineffective in removing contaminants outside of direct spray zones. Hence, sponging of surfaces soaked in proper disinfectant should be usually preferred.
Biosafety maintenance while transporting specimen to laboratories
The specimen container should be placed in leak-proof plastic biohazard specimen bags (secondary containers) and transported to laboratories. Specimens from confirmed COVID-19 patients should have a biohazard symbol on the outer container. To avoid accidental leakage or spillage, boxes fitted with racks should be used to carry so that the specimen containers remain upright. All details like the patient’s full name, date of birth, and a suspected case of COVID-19 should be written in the primary container and laboratory requisition form. Specimen request or specification forms should be placed in separate, preferably waterproof envelopes. Once received in the laboratory, these forms can be kept under an ultraviolet chamber, if available, to deactivate coronavirus if any. The intranet server system should be preferred to promote digital workflow. Through this, all requisition forms should be accessible to staff and clinicians online. Specific color coding should be used to mention the COVID status of the patient (positive, negative, suspected, recovered case, not tested). Persons involved in specimen transportation should be well trained in safe handling practices as well as spill disinfecting procedures. If infectious substances are spilled, then wear gloves and pour appropriate disinfectant over it, cover it with a cloth or paper and leave it for some time. The contaminated area should then be swabbed with disinfectant. Deliver all specimens by hand whenever possible. WHO recommends avoiding the use of pneumatic-tube systems to transport specimens. Transport of all specimens of suspected/diagnosed COVID-19 patients should be packed and shipped as UN 3373 Biological substance, Category B. The packaging for UN3373 consists of three components: (1) a water-tight, leak-proof primary receptacle (properly labeled), (2) a leak-proof secondary packaging with absorbent material to protect the primary receptacle, and (3) an outer packaging of appropriate strength with at least one surface having minimum dimensions of 100 mm × 100 mm. Upon receiving, the exterior of the specimen container should be disinfected.
Biosafety maintenance while handling specimens at laboratory
Laboratory amenities, based on construction, design features, containment facilities, practices, operational procedures, and types of equipment, can be assigned as basic—biosafety level 1, basic—biosafety level 2, containment—biosafety level 3, and maximum containment—biosafety level 4. These designations are required for working with any sample to conduct work safely in the laboratory. The routine laboratory procedures should be performed under biosafety level 2 (BSL-2). But, if experiments require the generation of high-concentration aerosols, then biosafety level 3 may be more appropriate to provide the necessary degree of safety because it ensures superior containment of aerosols in the laboratory workplace. [Table 1] summarizes the requirements of biosafety level-2 and -3. The international biohazard warning symbol and sign must be displayed on the doors of the rooms where samples of risk groups are handled. The laboratory doors should be kept closed and only authorized persons should be allowed to enter the laboratory working areas. Doors should have vision panels, appropriate fire ratings, and preferably be self-closing. When windows can be opened, they should be fitted with arthropod-proof screens. The specimen should be kept in an isolated area for 24 h before grossing, and a proper WHO’s Hand Hygiene approach should be followed. The grossing of specimens should be done after the requisite time of fixation with 10% neutral-buffered formalin (NBF). Small-sized specimens should be subjected for a minimum of 24 h and large size specimens for at least 48–72 h. Sometimes, cleaning and disinfection are not possible regularly due to restriction of resources; hence, regular washing of hands and avoid touching the face should be the basic prevention procedure to reduce contamination and transmission of the virus. [Table 2] and [Table 3] summarize the do’s and don’ts that the healthcare workers must follow for proper biosafety maintenance.
|Table 2: “At a glance” view of protocols that should be followed by laboratory health care workers|
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|Table 3: “At a glance” view of protocols that laboratory health care workers should avoid|
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Grossing gloves must be worn and the specimen should be handled with forceps. Eye and mucous membrane should also be protected using googles, face masks, and face shields. The lid of the tissue container should be grasped using gauze or paper to avoid splashing and the container should be opened gently. One portion of the lab should be separated for grossing of COVID-19-suspected/positive samples, where air conditioning systems should be switched off with basic amenities for cross ventilation facility and exhaust system. To avoid any contamination of infection, the assistance person should maintain a record of grossing details at a considerable distance from the working bench. Henwood discouraged the grossing of partially fixed specimens. He also inferred that cryostat usage may best be avoided due to the risk of aerosol generation. Proper precaution and control should be taken to reduce the formation and dispersion of aerosols. Class II biological safety cabinets must be used whenever high aerosol production procedures are performed. Working with frozen sections has been discouraged by the Royal College of Pathologists. If necessary, wear appropriate personal protective equipment (PPE) which should include fluid-resistant disposable gloves, fluid-resistant disposable apron, eye protection, and fluid-resistant (Type IIR) surgical mask (FRSM). The donning and doffing of PPE should be done in a specified area in the proper sequence and not inside the laboratory. The minimum number of operators should be present there and all dissections are needed to be performed in a ventilated/fume cupboard, which should be decontaminated following completion of work. Regular histotechnology processes in laboratories inactivate many viruses. A study by Darnell et al. showed that formalin and glutaraldehyde inactivated coronavirus in a temperature- and time-dependent manner. Formalin significantly decreased the infectivity of the virus on day 1 at 37°C/room temperature. It is, therefore, appropriate to consider that formalin-fixed tissues are less infectious. All contaminated materials, specimens, and cultures must be decontaminated with an Environmental Protection Agency (EPA)-approved disinfectant for SARS-CoV-2 before disposal or cleaning for reuse., Increase in temperature inactivates the virus, but higher humidity has an opposite effect.
Equipment for tissue processing should be of closed type, preferably jars and beakers, to avoid dispersion of droplets and aerosols. If automated tissue processors are used, it should be disinfected at the end of each session following the manufacturer’s instructions. The microscopic study by Xu et al. proclaimed that the SARS-2 virus was only present in lung tissue, whereas no viral change was seen in liver and cardiac muscle. Still, safety precautions should be taken while performing other procedures like embedding, sectioning, and staining. In a study, several coronalviruses were inactivated after subjecting to the following time and temperatures: 90 min at 56°C, 60 min at 67°C, and 30 min at 75°C. Paraffin infiltration during the day-to-day histotechnology process uses 60–65°C for 2 h or more. Hence, formalin-fixed paraffin-embedded tissue blocks are of less pathogenic risk. Refrigerators and deep-freezers should be defrosted and cleaned periodically. After cleansing, the inner surfaces of the cabinet should be properly disinfected. Only daily use of chemicals should be stocked in the laboratory. Bulk products should be kept separately in specially designated rooms or buildings. Training for cleaning staff in the laboratory, at the appropriate literacy level, about the proper procedures on disinfectant preparation and use should be mandatory.
All contaminated instruments and materials should be decontaminated before disposal. [Figure 1] summarizes the recommended list of disinfectants that are effective against SARS-2 and can be used in the laboratory. Steam autoclaving is the preferred method for all decontamination processes. Materials for decontamination and disposal should be placed in containers, e.g. autoclavable plastic bags, that are color-coded according to whether the contents are to be autoclaved and/or incinerated. All laboratory-generated biomedical waste must be disposed of as per institutional recommendations.
Reporting of specimen by pathologists
Pathologists can immerse slides in 95% alcohol for a few minutes before handling and interpreting slides. If reporting is done at a multi-header microscope, no more than three members are recommended at a given time, maintaining distance among themselves. The use of gloves and mask and adequate hand hygiene before and after reporting are compulsory. Microscopes should be sanitized by 70% alcohol solution on a regular basis, and all slides should be kept in closed boxes.
| Conclusion|| |
Each laboratory is advised by WHO to conduct its risk assessment to ensure that it can carry out the requisite tests adhering to the recommended biosafety practices and risk control measures. Good microbiological practices and procedures (GMPP) should be followed while handling and processing specimens. Healthcare workers need to be extremely careful in their workplace, which includes following proper protocol on donning and doffing of the PPE and complying to hand hygiene requirements. Proper signage and posters highlighting the steps of handwashing, doffing and donning of PPE, and safe laboratory practices may be used inside the laboratories. Remember, simple precautions and planning can make a big difference.
Simple precautions and planning can make a big difference. Stick to protocol, wear PPE, and follow the WHO hand hygiene technique to prevent the spread of the COVID-19 virus. Avoid overcrowding and maintain a social distance of 1 m in histopathology laboratories.
Financial support and sponsorship
Conflict of interest
There are no conflicts of interest.
AM—Article writing, first draft, and plagiarism check, PM—final draft and revision, KD—resources and literature search, LB—revision and plagiarism check, NM—editing and formatting, AP—conceptualization, revision, and final approval. Finally, all authors approved the article.
Ethical policy and institutional review board statement
Patient declaration of consent
Data availability statement
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[Table 1], [Table 2], [Table 3]