A surgical pathology laboratory accumulates all imaginable infectious material. The diversity of the material with scarce medical history on requisition forms makes the surgical pathology laboratory a special place of concern regarding worker’s infectious exposure vulnerability. The good old times when specimens arrived in fixative are gone forever. The requirements of modern pathology presume ancillary studies which do not tolerate tissue fixation. Under the pressure of turnaround time, the specimen is processed often in a fresh state.
Exposure Control Plans follow the OSHA Bloodborne Pathogens Standard (29 CFR 1910.1030).1 All employees who have occupational exposure to bloodborne pathogens receive initial and periodical training. Annual evaluation process includes safety tests. A surgical pathology laboratory now is incomparable with 20-30 years ago as far as safety concerns apply. However, there are many details of infection exposure that ought to be addressed.
Although other areas of pathology such as autopsy, cytology, cytogenetic, and clinical molecular biology also have their particularities of exposure to infectious agents, these materials discuss only the surgical pathology laboratory. Adherence to safety precautions in an autopsy suit is stricter than in the surgical pathology laboratory. It is remarkable that the Clinical and Laboratory Standard Institute’s (CLSI) “Protection of laboratory workers from occupationally acquired infection” guidelines devote seven pages to autopsy and one to surgical pathology. 2 However, given the current knowledge of potential infection exposures in the surgical pathology laboratory this imbalance is not right anymore.
This post concentrates on grossing in the surgical pathology laboratory as the most prone area to infection exposure. After tissue processor’s reagents and temperature, the histological block can be safely leaked, as histotechnologists used to say, although it would not be recommended either.
The OSHA Bloodborne Pathogens Standard (29 Code of Federal Regulations (CFR) 1910.1030) applies to all occupational exposures to blood or other potentially infectious materials (OPIM). The goal of this postis to add specifics of the surgical pathology practice with comments derived from practice. It is unnecessary to repeat the OSHA official materials although some of them will be quoted. The official Standard’s text is presented in italics in red.
“Universal precautions” is the fundamental notion of the OSHA Bloodborne Pathogens Standard. According to the OSHA Instructions for Enforcement Procedures for the Occupational Exposure to Bloodborne Pathogens, universal precautions are OSHA’s required methods of control to protect employees from exposure to all human blood and OPIM (Other Potential Infectious Material). The term “universal precautions” refers to a concept of bloodborne disease control which requires that all human blood and OPIM be treated as if known to be infectious for HIV, HBV, HCV or other bloodborne pathogens, regardless of the perceived “low risk” status of a patient or patient population. In regard to the surgical pathology laboratory practice, universal precautions mean that every specimen, as well as the laboratory working areas (grossing tables, reusable equipment) should be treated as potential source of infectious exposure.
These materials specifically use the term infectious exposure when OSHA standards prefer Bloodborn and Other Potential Infectious Material (OPIM). Regulations are written keeping in mind predominately clinical settings; because encounters with blood are the main working biohazard for them (syringes, tubes, phlebotomy, etc.). A surgical pathology laboratory is a small part of medical facility. In the surgical pathology laboratory, the “others” (soft tissue, bone, lymph nodes, content of cysts, abscesses, etc.) are dominating.
The OSHA Bloodborne Pathogens Standard includes, besides universal precautions, following main elements:
Engineering and work practice controls; Personal protective equipment; Housekeeping.
Engineering Controls and Work Practices
In the surgical pathology laboratory, the definition of engineering controls usually means specialized equipment. Engineering controls can contribute to infectious exposure prevention besides the standard collection of sharps. Devices for no-hand procedures in handling contaminated sharps, such as for blades removal can be employed, although these devices have limited use. However, correct work practices of removing blades from the handle using instruments (forceps) should be learned and followed as the obligatory practice. By the way, the habit of collecting used sharps in big containers to the lid, as often occurs, is wrong for many reasons.
Protection of working equipment as computers boards, photography devices, paper work supplies, and others can be conditionally related to engineering controls. Nevertheless, these actions ought to be done as an infection exposure prevention measure.
Power tools and devices may generate aerosolsas well as be a source for splashing and spattering. Some of these devices include requirements for local exhaust ventilation.
The Standard emphasizes environmental contamination by dried blood on the surfaces, needles, and instruments. This is a very important paragraph [(d) (4) (ii)] keeping in mind air conditioning and ventilation systems when the dried infectious material can be moved far from the working area and working space in the surgical pathology laboratory. This material can become pathogenic if propitious conditions were found (moisture, temperature). In surgical pathology practice, it means the necessity of immediate mechanical (with brushes ) cleaning, washing in soap detergents, rinsing in abundant water, as well as regular use disinfectants in the end of the working day after cleaning of reusable instruments, cutting boards, and work surfaces. Soaking in detergents overnight and during weekends is the right practice. Appropriate disinfectants include a diluted bleach solution and EPA-registered tuberculocides (List B), sterilants registered by EPA (List A), products registered against HIV/HBV (List D) or Sterilants/ High Level Disinfectants cleared by the FDA. Despite water is one of the “working tools” while grossing, the readily accessibility and the unit’s fully equipment with antiseptic hand cleaner is important.
Personal Protective Equipment (PPE)
According to OSHA, if engineering and work practice controls do not eliminate exposure, the use of personal protective equipment is required. In the surgical pathology laboratory, it is impossible to eliminate contact with biohazardous material because it is the essence of the procedure. Grossing cannot be automated in the same manner like in a clinical laboratory. The official OSHA materials regarding PPE are voluminous and self explanatory, but they require some comments.
Whether scrubs or laboratory coats, or both, are used, an additional covering is obligatory. Although an apron might be sufficient in many occasion, optimal is a disposable gown like plastic blue aprons. They are easily manageable, though uncomfortable when physical work or in hot ambient temperature.
Masks in combination with eye protection devices, such as goggles or glasses with solid side shields, or chin-length face shields, shall be worn whenever splashes, spray, spatter, or droplets of blood or other potentially infectious materials may be generated and eye, nose, or mouth contamination can be reasonably anticipated.
The use of masks and eye protection is underestimated in the surgical pathology laboratory, although gradually is more and more implemented. However, only a proper use is useful. The practical aspects of mask use will be presented the section “Bloody specimens”.
Eye protection glasses should be an obligatory component of every day PPE in a surgical pathology laboratory. Goggles are impractical and superfluous. By my grim experience of many accidents, I developed a constant rule as stepping in the laboratory with my safety glasses on and keeping them on until I am out from the laboratory. Although this habit came from formalin protection, it is valid for infection exposure. Unfortunately, the modern safety glasses designs try to follow the frame fashions leaving many spaces open that is unacceptable.
Gloves are used in surgical pathology laboratory for protection from infectious exposure, mechanical injury, as well as a barrier of chemical damage to the skin. In surgical pathology, the work involves manual manipulation including cutting and stretching, where unnoticed piercing might occur under conditions of chemical weakening of the glove’s structure. These circumstances require additional attention to the glove’s permeability. In some situations, it is reasonable to use double gloves (bone processing). It seems that nitrile gloves have some preferences in durability and resistances to stretches that is important in heavy duty work with bones and other large specimens, but for biopsies latex gloves are cheaper and suitable for frequent changing and greater visibility if the glove were damaged although many laboratories do not use them anymore due to an increase in latex allergies.
According to the OSHA Standard, surgical caps or hoods and/or shoe covers or boots shall be worn in instances when gross contamination can reasonably be anticipated (e.g., autopsies, orthopedic surgery). In the surgical pathology laboratory, shoe covers are superfluous, but caps would be appropriate for many reason (splashes, aerosols, absorption smells and chemicals by hair), although usually they are avoided except both, shoe covers and hair caps are demonstrated in some laboratories when a commission arrives for an inspection, just in case.
The OSHA Standard distinguishes between work area and work site. This difference has practical sense for infection exposure prevention in surgical pathology laboratory.
The term “work area” means the area where work involving exposure or potential exposure to blood or OPIM exists, along with the potential contamination of surfaces. In the surgical pathology laboratory practice, it means cleaning the working table after completion of grossing procedures that belongs to working practices category that is described before.
The term “worksite” in the Housekeeping paragraph refers to permanent fixed facilities such as hospitals, dental/medical offices, clinics, etc. it means cleaning the area immediately adjacent to the work area in a surgical pathology laboratory. The worksite should be responsibly determined by management for housekeeping.
In the surgical pathology laboratory with vast potentially infectious material, the worksite’s floors should be disinfected. A realistic suggestion would be at least surrounding the main working areas as grossing tables/stations, frozen section, accession at the end of the work shift. Disinfection of this worksite should be implemented and controlled.
Periodical scheduled mopping is in addition to everyday cleaning. This procedure requires moving bulky grossing stations which have many areas inaccessible to everyday cleaning, but might be a place of collection of dried blood and OPIM or even a hotbed for pathogenic microorganisms. While choosing equipment for a surgical pathology laboratory, especially grossing stations, the accessibility for cleaning should be considered.
Universal precautions provisions ought to start at the specimen receipt and accession level. This area is underestimated in regard of infection exposure prevention. During the accession, the specimen is taken out from the transport bag. The bags and containers sometimes are contaminated with blood or OPIM. Needless to say, that some accidents can occur during the automated transport of specimens, like unpacking of the transportation bags or even the containers. There is a cavalier approach to PPE of accession and housekeeping personnel. All precautions and standards not apply in this situation. Additional measures of cleaning and disinfection should be determined and enforced.
However, some surgical pathology specimens and area of work require special attention due to significant possibility of infection exposure. Frozen section laboratory, bone grossing, as well as “bloody specimens” can be mentioned in the first place.
1. OSHA Bloodborne Pathogens Standard, 29 C.F.R. Sect. 1910.1030 (2008).
2. Clinical and Laboratory Standard Institute (CLSI): Protection of Laboratory Workers from Occupationally Acquired Infections; Approved Guideline—Third Edition, M29-A3 Vol 25 No. 10 2005.