Bloodborne pathogens (BBPs) represent a serious occupational hazard in any environment where exposure to human blood or other potentially infectious materials (OPIM) is possible. Selecting the correct personal protective equipment (PPE) is the primary method of creating a barrier against these risks. The standard cloth laboratory coat provides minimal defense and is insufficient for high-risk tasks involving splatter or fluid exposure. True protection relies on specialized, fluid-resistant apparel engineered specifically to prevent the passage of infectious liquids.
Regulatory Requirements and Protective Standards
The necessity for appropriate protective apparel is mandated by the Occupational Safety and Health Administration (OSHA) Bloodborne Pathogens Standard. This regulation requires employers to provide protective clothing that does not allow blood or OPIM to pass through to the employee’s underlying clothing, skin, or mucous membranes under normal conditions of use. The term “lab coat” may be used, but the garment must meet a specific performance standard, which traditional cotton or polyester coats fail to achieve.
The performance of protective apparel is standardized by the American National Standards Institute/Association for the Advancement of Medical Instrumentation (ANSI/AAMI) PB70 classification system. This system categorizes gowns and protective clothing into four levels based on their barrier effectiveness against liquids. The level required depends on the anticipated risk of fluid exposure during the task.
For procedures involving bloodborne pathogens, the required protection level is almost always Level 3 or, ideally, Level 4. Level 3 provides moderate barrier protection, suitable for situations like arterial blood draws or inserting an intravenous line where the risk of fluid exposure is moderate. Only Level 4 garments are designed for the highest risk of exposure, such as during long, fluid-intense procedures.
A Level 4 garment is the only classification that must pass a specific test for viral penetration, ASTM F1671, using a surrogate virus. This test ensures the material is impermeable to viruses carried in blood, unlike Levels 1 through 3, which are only tested for water resistance. A protective gown or coat must be clearly labeled as ANSI/AAMI Level 4 for the maximum assurance of protection against bloodborne pathogens.
Material and Design Specifications
The superior barrier performance of Level 4 apparel is achieved through its construction and material science, differing significantly from common woven fabrics. These protective gowns are typically made from multi-layered non-woven materials such as SMS fabric, which stands for spunbond-meltblown-spunbond. The central meltblown layer consists of densely packed microfibers that create an effective physical barrier against fluid penetration.
For the highest level of fluid resistance, the fabric is often coated with or incorporates a layer of polyethylene (PE) film, which is an impervious plastic material. This poly-coated spunbond material ensures that blood and OPIM cannot soak through, even under pressure. Traditional lab coats made of cotton or cotton-polyester blends are porous and allow liquids to wick or strike through quickly, rendering them ineffective against BBPs.
The design of the garment is as important as the material composition in preventing exposure. Protective apparel for BBPs must provide full coverage of the torso and limbs, often taking the form of a gown rather than a traditional front-opening lab coat. A full back closure is preferred, as it eliminates the gap found in the back of most standard lab coats. Essential features also include knit cuffs or elastic wrist loops, which create a snug seal around the wrist and prevent infectious fluids from wicking up the sleeve or contacting the skin.
Proper Use, Removal, and Handling
The protective apparel must be correctly worn to maintain its barrier integrity throughout the procedure. This involves selecting the correct size to ensure the gown fully covers the torso, arms, and extends to the knees. The cuffs must be positioned securely under the gloves to create a continuous sealed barrier from the fingers to the neck. If the garment becomes visibly soaked, torn, or otherwise compromised, it must be removed and replaced immediately.
The procedure for taking off the protective coat, known as doffing, is a contamination-control process. The outside of the garment is considered heavily contaminated and must never touch the user’s skin or clothing. The proper technique requires the user to first untie the fasteners and then pull the gown away from the neck and shoulders, touching only the inside surfaces.
The garment should be turned completely inside-out as it is peeled off the arms, folding the contaminated exterior into a bundle. This action effectively wraps the infectious material within the garment before it is immediately discarded into a designated regulated waste container. Performing hand hygiene, either by washing hands or using an alcohol-based hand rub, must be done immediately after the removal of any protective apparel to eliminate any residual contamination.