Coronavirus disease 2019 (COVID-19) was first detected in China in December 2019, and declared as a pandemic by the WHO on March 11, 2020 (1–3). During the period of COVID-19, the specimens of blood, body fluids, and excreta received in the department of pathology increased the risk of infection (4, 5). Pathology technicians in the middle- and small-scale hospitals, which are short of professional protection capabilities, such as negative pressure laboratories and microbiology laboratories, are more susceptible to virus infection, as they are often exposed to a variety of pathological samples of patients (6, 7). Besides, as the specimen collected for clinical examination is of great uncertainty, it is easy for medical staff to be infected by sputtering or aerosol after opening the sample boxes directly (8). In some backward areas, medical staff cannot be evenly equipped with N95 masks, goggles, and protective clothing. Therefore, an efficient way is needed for the test of pathological specimens during the pandemic (9). Here, we proposed a simple and feasible way to pretreat sputum samples by contactless disinfection, and cell smears, liquid-based cell staining, and immunohistochemical staining were performed to investigate whether this new method could affect the pathological observation and cell antigen expression in the samples of patients with lung cancer (10).

In January 2020, China reported the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that was further declared as a pandemic owing to rapid spread to different parts of the world (12). Although COVID-19 is a contagious disease that spreads rapidly via droplet particles arising through sneezing and coughing action of an infected person, COVID-19 Diagnosis and Treatment Protocol (Trial version 6), released by the National Health Commission (NHC) on 19 February 2020 pointed out the possibility of virus transmission through aerosols when prolonged exposure to high concentrations of aerosols in a relatively closed environment (13).

During COVID-19 pandemic, pathological specimens, such as sputum and lavage fluid, from the department of respiratory and emergency may be at risk of infecting medical staff. Thus, sputtering and aerosol transmission are very likely to occur if specimens are processed routinely. At present, pathology departments in some middle- and small-scale hospitals are still suffering from a lack of a simple and efficient way to process the cytological specimen without destruction of cell morphology. What is more, some middle- and small-scale hospitals were not even equipped with professional negative pressure laboratories and biosafety cabinets, which may cause cross-infection among medical staff during the process of handling pathological specimens. In addition, it is very likely to trigger contact infection by aerosol if specimen boxes containing samples are opened directly.

As the cytological examination of sputum and lavage fluid is the major way to diagnose respiratory diseases, we first propose a new and economic way to process the specimens efficiently. In this study, we used a sealed bag to keep the sputum sample in a closed space, and then pretreated it with 75% medical alcohol to sterilize the sample, to protect the technician and other staff against the virus. The sealed pathological specimen bag has good corrosion resistance and fastness, and is not easy to be damaged during operation. The rubber band was used to prevent the alcohol from shaking in the bag. The seal strip was used to isolate the virus that may exist after the sample box was opened. As the 75% medical alcohol can cause protein coagulation, which may affect the sputum cytology test. In this study, we verified that the cell morphology and cell antigens expression are not affected after medical alcohol pretreatment by using cell smears, liquid-based cell staining, and immunohistochemical staining. Thus we conclude that this method has the advantage of being low cost and easy to operate, it is worth popularizing and applying in pathology departments, especially hospitals in backward areas.

This study provided a new method for technicians to test samples that may contain pathogenic bacteria or viruses without direct contact to protect medical staff against viruses during COVID-19 outbreak.

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author/s.

The studies involving human participants were reviewed and approved by ethics committee on human research at Shanghai Jiaotong University, School of Medicine, Shanghai Ninth People's Hospital. The patients/participants provided written informed consent to participate in this study.

JC and XW wrote the manuscript and contributed equally to this work. LL, TJ, and YR conduct experimental research, organize experimental data into manuscripts, and supervised the findings of this work. All authors contributed to the article and approved the submitted version.

This study was supported by the Sponsored by Shanghai Sailing Program (No. 19YF1427600) and the National Nature Science Foundation of China (No. 81900438).

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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