Shared manual methods and lax attention to personal protective equipment (PPE) appear to be the greatest risk points for laboratory-acquired infection, a study in Clinical Chemistry found. Investigators analyzed the likelihood of instrument contamination from grossly contaminated specimens in labs and discovered that while the likelihood is low, only 50% of lab staff consistently washed their hands according to standard operating procedures, enhancing risk of contaminating specimen containers.

Little data exist on cross-contamination risk to specimens and instruments in labs during routine testing. To find out where those risks lie and how they should be evaluated, a team of clinical lab researchers conducted several experiments. First, they applied a  fluorescent marker to specimen collection tubes before processing the specimens, using ultraviolet light to assess fluorescent transfer to surfaces, equipment, and laboratory staff. They also added a nonpathogenic Bacteriophage MS2 virus to remnant blood, urine, and ESwab specimens to determine cross-contamination risk.

The investigators swabbed and analyzed surfaces for MS2 contamination using reverse transcription polymerase chain reaction testing. They also used the Roche Cobas 8100 and ISE, c502, e602, and c702 modules and BD Kiestra instruments to process and analyze samples. In an additional step, they directly observed how lab staff members used PPE.

While they found no surface contamination in the MS2 experiment, investigators did report fluorescence on 30% of laboratory surfaces and personnel and 23% of total laboratory automation instruments. Gloves, computer accessories, and specimen loading racks were the highest traffic areas for fluorescence transfers. In perhaps the most sobering news, only 61 of 132 staff (46%) complied with handwashing procedures, and improper use of PPE took place

at a rate of 0.36 events per staff per hour in the chemistry labs and 0.15 events in microbiology labs.

This indicated that handling contaminated specimen containers can lead to contaminated lab surfaces. Poor compliance with PPE exacerbates this risk, the researchers concluded. “Previous studies suggest that contributing factors to PPE noncompliance in healthcare settings may be multifactorial. The need for PPE and meticulous hand hygiene is further heightened in the setting of a global pandemic such as Coronavirus Disease 2019,” Jonathan R. Genzen commented in a related editorial.

The results suggest that automation could help reduce contamination caused by manual handling of specimens, wrote Genzen, chief operating officer of ARUP Laboratories in Salt Lake City. “Priority routing of specimens through a [total laboratory automation] system (i.e., directing specimens intended for molecular diagnostics immediately to such instrumentation) may help to mitigate contamination risk. However, such strategies may also not fully reflect real-world practices and procedures, including shared decapping and centrifugation modules, specimen reloading, reroutes, and challenges in resolving definitive container identification,” he added.

Genzen acknowledged that it’s difficult to eradicate microbial contamination in labs. That said, clinical labs should be clean enough to prevent infection risks, preserve the safety of employees, conduct testing in the most efficient manner possible and prevent contamination risks that could affect specimen results.

Read more about microbial contamination risk in September’s Clinical Chemistry.