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FROZEN SECTIONS, FINE NEEDLE ASPIRATIONS AND RENAL BIOPSIES

The use of intra-operative frozen section examination, as well as cytological assessment of a fine needle aspiration in theatre or in the radiological setting, can yield vital diagnostic and/or prognostic information in a timely manner.

During this COVID-19 pandemic, we have to weigh up the benefits of these procedures versus the potential risks to the pathologist and pathology staff. The problem is further aggravated by the fact that a patient may be asymptomatic but infectious at the time of the procedure, even though most hospitals have now implemented mandatory pre-admission screening for the SARS-CoV-2 virus. In view of the above, and as pathologists do not dress in full theatre apparel as the operating clinicians, it is best to regard all specimens as potentially SARS-CoV-2 infected. Also important, hospitals prefer to limit the travelling of doctors between different hospital complexes.

Both the College of American Pathologists (CAP) and the Royal College of Pathologists (RCPath) have issued statements addressing this issue. The risk of aerosol production during frozen section varies, depending whether a closed cryostat (low risk) or a CO2 microtome using gas under high pressure (high risk) is used. The risk for FNA is regarded as extremely low. However due to the possibility of droplet exposure both the CAP and RCPath advised that any tissue dissection or processing of cytology fluids must preferably be performed in a ventilated safety cabinet. Some of the clinical societies have also commented on this issue. The European Association of Urologists has advised its members to refrain from submitting fresh tissue for frozen sections during the pandemic.

In view of the above, we recommend the following guidelines:

1) Frozen sections, renal biopsies and FNA’s are only performed on patients who have been screened and are COVID-19 negative.
2) Where there is a recognised alternative management protocol, where a frozen section is not required, it must preferably be followed. Examples are sentinel lymph nodes in breast cancer and pre-operative biopsies to delineate the field of plastic surgery rather than a frozen section to confirm adequacy of resection.
3) All dissections of fresh tissue for frozen sections or renal biopsies, as well as the handling of fresh cytology fluids, should ideally be performed in a ventilated biosafety cabinet, if available.
4) All bookings must only be made after consultation between the surgeon and a pathologist.

We realise the important role of a comprehensive histopathology service in surgical practice, but we believe that this “new normal” practice will assist clinicians to continue practice.

STATEMENT ON THE USE OF SINGLE NASO- OR OROPHARYNGEAL SWAB FOR SARS-CoV-2 PCR

The National Institute for Communicable Diseases (NICD) recently updated their sampling recommendations to include the use of a single nasopharyngeal swab or an oropharyngeal swab for the diagnosis of COVID-19.

The National Pathology Group (NPG) supports this recommendation as it is in line with US Centers for Disease Control and Prevention (CDC) guidance while South Africa continues to face restricted availability of essential supplies required for the diagnosis of COVID-19, including swabs.

There is no compelling evidence for a significantly increased sensitivity of a combination of naso- and oropharyngeal swabs over the use of a single swab. Limited studies have found the yield of nasopharyngeal swabs to be higher compared to oropharyngeal swabs, and the NPG therefore advises the use of a single nasopharyngeal swab over a single oropharyngeal swab where possible.

We also want to reiterate that samples taken from the lower respiratory tract such as sputum, tracheal aspirate and bronchoalveolar lavage are preferred over swabs in patients who present with lower respiratory tract disease.