Medical laboratory directors and pathologists are likely to find their lab’s safety standards increasingly under the spotlight

Clinical laboratories and pathology groups should be aware of new safety guidelines that address the risk of laboratory-acquired infections (LAI). A panel of experts convened by the Centers for Disease Control and Prevention (CDC) recently released safety guidelines for medical laboratory workers.

The guidelines are intended to improve safety specifically in diagnostic laboratories that handle specimens from humans and animals. Statistics indicate the clinical laboratory workers have infection rates for certain diseases that can be up to 20 times greater than that of the general population! It is believed current data understate the true rate of laboratory-acquired infections within the nation’s medical laboratories and pathology groups.

The report is titled Guidelines for Safe Work Practices in Human and Animal Medical Diagnostic Laboratories: Recommendations of a CDC-convened, Biosafety Blue Ribbon Panel. (The URL for the report is: http://www.cdc.gov/mmwr/preview/mmwrhtml/su6101a1.htm.)

According to a story on the Center for Infectious Disease Research & Policy (CIDRAP) website, the CDC assembled a “Biosafety Blue Ribbon Panel of experts from the CDC and a number of university and private labs.” It was this group that compiled the clinical laboratory safety guidelines.

The blue-ribbon panel issued its report calling for the creation of a voluntary, non-punitive, surveillance and reporting system for laboratory-acquired infections.

Reducing the number of laboratory-acquired infections in clinical laboratories and anatomic pathology laboratories is one primary goal behind issuance of voluntary safety guidelines developed by a Biosafety Blue Ribbon Panel convened by the Centers for Disease Control and Prevention (CDC). The new safety guidelines were published in January in the CDC’s Morbidity and Mortality Weekly Report. (image from the CDC.)

The material in the report originated in the National Center for Emerging and Zoonotic Infectious Diseases, a division of CDC’s Office of Infectious Diseases. It is intended as a supplement to Morbidity and Mortality Weekly Report, CDC’s primary vehicle for publication of public health information and recommendations. The panel included experts from the CDC, as well as several university and private laboratory organizations.

Among the experts that reviewed the panel’s recommendations were representatives from the College of American Pathologists (CAP), American Society for Microbiology, American Clinical Laboratory Association (ACLA), Association of Public Health Laboratories, along with other participating organizations.

This story starts back in 2008. That is when the CDC first convened the panel of laboratory representatives from a variety of agencies, laboratory organizations, and medical laboratory organizations. The assembled panel members reviewed laboratory biosafety in diagnostic laboratories.

The panel made two broad recommendations. First, it called for the development of biosafety guidelines to address the unique operational needs of the diagnostic laboratory community. Second, it recommended that the biosafety guidelines be science based and made easily available to the medical laboratory profession.

In general, the new guidelines’ general aims are to improve safety in clinical laboratories, encourage lab workers to think about safety issues, and encourage a culture of safety. “The goal of a safety program is to lower the risk [of laboratory-acquired infections] to as close as possible to zero,” the report stated.

Dearth of Science-Based Insights on Prevention of LAIs

The report noted that, as of 2008, the U.S. Bureau of Labor Statistics estimated that about 328,000 medical laboratory technicians and technologists worked in human diagnostic laboratories in the United States.

Prevention of injuries and occupational infections in these laboratory workers has been a concern for many years, the report pointed out. However, except for a limited program covering certain dangerous biological agents and toxins, there is no national system for reporting medical laboratory exposures and infections that may result.

“Because of the lack of an official surveillance mechanism for reporting LAIs and because of the fear of punitive action by an oversight agency if injuries are reported, the data needed to determine the extent and cause of LAIs are unavailable,” noted the report. “In addition, there is a dearth of science-based insights on prevention of LAIs.”

Medical Lab Workers Become Infected at Higher Rate than General Public

“Laboratory exposures occur more often than is generally suspected,” the report revealed. The panelists reviewed and presented data that shows the higher risk of LAIs faced by medical laboratory workers. The following are examples of that data:

• Early surveys of LAIs found that laboratory personnel were three to nine times more likely to become infected with Mycobacterium tuberculosis.
• In a 2005 CDC study of Neisseria meningitides (NM), the numbers showed the attack rate in the general population was 13 per 100,000. The attack rate in the general population aged 30-59 (the estimated age range of the average laboratorian) was 0.3 per 100,000. The attack rate of NM for microbiologists in that same age range was 20 per 100,000, almost 20 times the general population rate of infection for that age group.
• Hepatitis B has been the most frequent laboratory-acquired viral infection. The rate of infection in laboratory workers, 3.5-4.6 per 1,000, is two to four times the rate in the general population.

The safety guidelines identify the five most predominant routes of LAIs. They are:

1. Parenteral inoculations with syringe needles or other contaminated sharps;
2. Spills and splashes onto skin and mucous membranes;
3. Ingestion or exposure through mouth pipetting or touching mouth or eyes with fingers or contaminated objects;
4. Animal bites and scratches (research laboratories or activities); and
5. Inhalation of infectious aerosols.

The first four causes are relatively easy to detect, the report stated. However, the panel noted that they account for less than 20% of all reported LAIs. The report suggested that unsuspected infectious aerosols may play a significant role in the remaining 80% of LAIs.

At this time, as published by the CDC, the “Guidelines for Safe Work Practices in Human and Animal Medical Diagnostic Laboratories,” are voluntary. They are designed to encourage pathologists, clinical lab administrators, and all lab scientists to devote more attention and resources within their labs on the prevention of laboratory-acquired infections.

However, by including statistics that demonstrate how the infection rates among medical laboratory workers can be measurably higher when compared to the general population, the CDC’s Biosafety Blue Ribbon Panel has laid an important marker on the table for the entire clinical laboratory testing profession. Conscientious lab leaders will want to study these guidelines and then take active steps within their respective laboratory organizations to better protect their lab workers from laboratory-acquired infections.

—Pamela Scherer McLeod

Related Information:

Experts say US needs better tracking of lab accidents

Guidelines for Safe Work Practices in Human and Animal Medical Diagnostic Laboratories: Recommendations of a CDC-convened, Biosafety Blue Ribbon Panel

Health of Pathology Laboratory Technicians at Risk from Common Solvents like Xylene and Toluene

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