Background The outbreak of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been declared as a public health emergency of international concern and then reclassified as a pandemic by the WHO [1,2]. Similar to severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), SARS-CoV-2 is a β-coronavirus causing mainly pneumonia with high mortality rates [3,4]. In this global crisis, numerous healthcare professionals and laboratory workers still work daily to combat the COVID-19 pandemic. In particular, personnel in bioanalytical laboratories who handle clinical samples, now need to take new special precautions in the event these samples are SARS-CoV-2 positive. Therefore, the purpose of this commentary is to summarize the viral load and infectious risk of SARS-CoV-2 in different biological matrices based on recent reports. The effectiveness of the published viral inactivation protocols before sample processing and their potential interference with bioanalytical assays are also reviewed. Here, we also discuss appropriate laboratory operations to minimize exposure risks. We hope that the bioanalytical community can benefit from this article by understanding the risk of SARS-CoV-2 transmission when handling clinical specimens from COVID-19 patients and improving laboratory biosafety practices. SARS-CoV-2 viral load in biological matrices A main safety concern for bioanalytical laboratories handling COVID-19 patient samples is the SARS-CoV-2 viral load in biological matrices. Some recent studies have reported SARS-CoV-2-positive detection rates in patient specimens. Most of these studies employed reverse transcription-polymerase chain reaction to detect viral RNA for the diagnosis of SARS-CoV-2 infection [5,6]. Although the statistical data vary somewhat due to the difference in sample size and patient's disease severity, the observations were generally consistent. Since the virus primarily targets the respiratory system, positive rate of SARS-CoV-2 was the highest in respiratory matrices as expected, with higher viral loads detected in lower respiratory specimens (e.g., bronchoalveolar lavage fluid and sputum) than upper respiratory specimens (e.g., nasal swab and throat swab). Wang et al. collected 1070 specimens from 205 COVID-19 patients with the mean age of 44 years (range from 5 to 67 years and 68% were male) [7]. Most patients showed symptoms of fever, dry cough and fatigue; 19% of patients had severe illness. SARS-CoV-2 was positively detected in 14 of 15 (93%) bronchoalveolar lavage fluid, 75 of 104 (72%) sputum, five of 8 (63%) nasal swabs, 126 of 398 (32%) throat swabs, 44 of 153 (29%) feces, three of 307 (1%) blood and none of 72 (0%) urine [7]. Yu et al. analyzed 323 specimens from 76 COVID-19 patients with the median age of 40 years (range from 6 months to 92 years and 50% were male) [5]. The major symptoms were fever (88.2%) and cough (69.7%); 77.6% of patients were the mild type...