TABLE 8.

Laboratory procedures that may require different biosafety level precautions ⁷¹

Biosafety level 2 (BSL‐2) precautions	Biosafety level 3 (BSL‐3) precautions
Flow cytometry of formaldehyde‐fixed specimens	Procedures with human or animal primary specimens to intentionally concentrate or isolate SARS‐CoV‐2 for research purposes (eg, ultracentrifugation of a sample)
Cell sorting with FACS Sorter has to be performed in the closed tube system. If a plate sort is necessary, the aerosol protection has to be used	Culturing specimens (eg, propagated virus)
Assays with virus‐inactivated specimens	Preparatory work for in vivo activities
Concentration of samples prior to inactivation	Processing a culture (eg, propagated or cultivated) known to contain SARS‐CoV‐2 for packaging and distribution to laboratories
Sample preparation for nucleic acid extraction, flow cytometry analysis, molecular testing of nucleic acids	Preparing inoculum, inoculating animals and collecting specimens from experimentally infected animals
Antigen and antibody assays	Virus neutralization tests for blocking activity against SARS‐CoV‐2 (with live virus)