Grossing Stations

A grossing station is a specialized laboratory workstation designed for the dissection, examination, and documentation of tissue specimens in pathology labs. It provides a dedicated, ergonomically designed space where pathologists or histotechnologists perform the “grossing” process—preparing tissue samples for further histological analysis. These stations are equipped with features such as cutting surfaces, sinks, lighting, and integrated ventilation systems to ensure a safe, efficient, and contaminant-controlled environment. Because the grossing process may involve exposure to biological materials and chemical fixatives like formalin, grossing stations are also designed with airflow and filtration systems to protect users from harmful vapors and particulate matter. They are an essential component in surgical pathology, ensuring both specimen integrity and technician safety.

What is a Grossing Station

Airflow

Proper airflow in a grossing station is critically important for protecting laboratory personnel from exposure to potentially hazardous fumes, aerosols, and biological particles released during the dissection and examination of tissue specimens.

These workstations often involve the use of chemicals such as formalin, which can emit toxic vapors. To minimize inhalation risks and maintain a safe work environment, grossing stations are designed with integrated ventilation systems that create a consistent downward or rear-directed airflow, pulling contaminated air away from the technician’s breathing zone. This air is then filtered or ducted away through exhaust systems, often incorporating HEPA and carbon filters for particulate and chemical removal. Effective airflow not only safeguards staff health but also helps maintain compliance with laboratory safety standards and occupational exposure limits.

Airflow Configurations in Grossing Stations

Grossing stations are engineered with specific airflow configurations to efficiently capture and remove fumes and particulates generated during the tissue processing workflow. The most common setup is downward airflow, where air is pulled from above the work surface and drawn through perforated grilles into an integrated exhaust system below. This creates a consistent, protective barrier between the technician and any hazardous emissions. Some stations also utilize rear-directed airflow, where air is drawn horizontally from the front opening toward rear exhaust vents behind the work surface. In advanced designs, a combination of downward and rear-extraction airflow may be used to maximize containment, especially when large tissue samples or containers of formalin are involved. These configurations help ensure that any airborne contaminants are rapidly removed before they can enter the technician’s breathing zone.

Filtration Systems in Grossing Stations

To ensure safe air quality and regulatory compliance, grossing stations often integrate multi-stage filtration systems designed to capture both particulates and chemical vapors.

Air that is drawn into the station typically passes first through a pre-filter, which captures large particles and biological debris, extending the life of downstream filters. Next, a HEPA (High-Efficiency Particulate Air) filter is used to remove fine airborne particles with an efficiency of 99.97% at 0.3 microns.

To handle volatile chemicals such as formaldehyde and xylene, a carbon filter is typically included to adsorb vapors and neutralize odors. In ducted systems, the filtered air may be vented externally, while in ductless (recirculating) grossing stations, the clean air is returned to the room after passing through all necessary filtration stages. The choice between ducted and ductless filtration depends on chemical volume, facility layout, and local safety regulations.

Filters

1. Activated Carbon Filters (Standard)

These filters are designed to adsorb a broad range of chemical vapors, including low concentrations of formaldehyde. They're commonly used in ductless or recirculating grossing stations, where filtered air is returned to the room. While effective for general lab chemicals, they may have limited capacity for sustained or high-level formaldehyde exposure.

2. Formaldehyde-Specific Carbon Filters

These are impregnated or chemically treated carbon filters that are specifically enhanced to capture and neutralize formaldehyde more effectively than standard activated carbon. They're often labeled as "formaldehyde filters" or "formaldehyde-specific adsorbents." These filters are ideal for labs that routinely use formalin, as they provide greater efficiency and saturation capacity.

3. Multi-Stage Filtration Systems

Some grossing stations combine pre-filters, HEPA filters, and chemical filters in a multi-stage setup:

Pre-filter: Captures large particulates and biological debris.
HEPA filter: Removes fine particulates, including potential biological contaminants.
Chemical filter (formaldehyde-specific or general carbon): Adsorbs chemical vapors such as formaldehyde and xylene.