Professional Design and Construction of the Grossing Room, Tissue Processing & Embedding Room, and Sectioning Room
Within a precisely planned spatial system, every tissue specimen moves step by step—from the human body to a diagnostic slide—along a carefully controlled technical pathway.
In a pathology department, once a tissue specimen enters the laboratory, it immediately begins a series of standardized and irreversible procedures. Technicians first perform grossing, then proceed through dehydration, embedding, sectioning, and staining. Each step directly affects diagnostic accuracy and reliability.
Therefore, the grossing room, tissue processing and embedding room, and sectioning room form the core functional spaces that support this transformation.
Together, these three zones establish the primary tissue-processing workflow of a pathology laboratory. If designers overlook workflow coordination, environmental control, or safety requirements, specimen contamination, identification errors, and diagnostic delays may occur. For this reason, designers must integrate process logic, engineering controls, and regulatory compliance from the very beginning.
01 Core Layout
Establishing the Logical Foundation of Pathology Laboratory Design
First, an efficient pathology laboratory must follow the natural sequence of tissue processing.
Designers should position the grossing room as the first operational node and connect it directly to specimen receiving areas, surgical access routes, and emergency pathways. By doing so, the laboratory reduces specimen transfer time and limits unnecessary personnel movement.
Next, designers should locate the tissue processing and embedding room at the center of the workflow. This positioning allows the room to efficiently link grossing activities with downstream technical operations while supporting centralized equipment installation and independent ventilation.
Then, designers typically place the sectioning room adjacent to staining and coverslipping areas. This arrangement creates a continuous technical work line and minimizes repeated specimen handling.
As a result, this linear or semi-linear layout improves operational efficiency, shortens transport distances, and significantly reduces the risk of cross-contamination.
To ensure balanced spatial allocation, designers should calculate room sizes based on specimen volume and equipment configuration. In practice, typical area ratios include:
- Grossing room: 15–20%
- Tissue processing & embedding room: 25–30%
- Sectioning room: 15–20%
- Remaining area: auxiliary and support spaces
02 Core Functions
Defining the Roles and Configurations of the Three Key Areas
Grossing Room: Establishing the First Line of Specimen Control
First, the grossing room serves as the operational frontline of the pathology laboratory. Here, staff perform the initial handling and sampling of surgically excised specimens.
To support this work, designers must equip standardized grossing stations with:
- High-efficiency local exhaust ventilation
- Uniform, shadow-free task lighting
- Convenient rinsing and waste collection systems
Moreover, engineers must design the ventilation system specifically to control exposure to formaldehyde and other hazardous substances, thereby protecting staff safety.
When laboratories handle high-risk cases such as tuberculosis or hepatitis, they must also install biological safety cabinets.
In addition, modern grossing rooms routinely include specimen refrigerators, instrument disinfection equipment, and digital imaging systems to improve efficiency and traceability.
Tissue Processing and Embedding Room: Supporting the Technical Core of Tissue Handling
Next, the tissue processing and embedding room houses fully automated tissue processors and embedding centers, making it the most equipment-intensive zone in the laboratory.
Because tissue processors release reagent vapors and generate liquid waste during operation, engineers must provide independent ventilation and drainage systems. By isolating these systems, the laboratory prevents chemical odors and contaminants from affecting adjacent areas.
Furthermore, the embedding area requires a clean and thermally stable environment. Cold plates, paraffin dispensers, embedding stations, and cooling plates together form a complete embedding workstation.
To maintain paraffin stability and ensure consistent embedding quality, operators should keep ambient temperature between 20–24°C.
Sectioning Room: Ensuring Slide Quality for Accurate Diagnosis
After embedding, specimens move to the sectioning room, which directly determines final slide quality. Consequently, this room represents one of the most sensitive operational environments in the pathology laboratory.
Technicians rely on paraffin microtomes as the core equipment. Therefore, engineers must install microtomes on anti-vibration tables, since even minimal vibration can compromise section thickness and integrity.
Additionally, laboratories should equip the sectioning room with water baths, slide dryers, and ultraviolet disinfection devices to support a complete and efficient workflow.
To prevent section curling, cracking, or adhesion defects, facility managers must tightly control environmental conditions:
- Temperature: 22–25°C
- Relative humidity: 50–60%
03 Key Construction Considerations
Using Engineering Details to Define Laboratory Quality
Above all, the ventilation system plays a decisive role in pathology laboratory performance.
Designers must maintain the grossing room under negative pressure, ensuring airflow consistently moves from clean zones toward contaminated areas. Meanwhile, they should provide the tissue processing and embedding room with independent exhaust systems to prevent reagent odors from spreading.
At the same time, electrical systems must support both high power demand and operational stability. Engineers should supply precision instruments—such as microtomes—with voltage stabilizers and dedicated grounding.
Moreover, lighting design must prioritize task areas. At grossing stations and sectioning work zones, illuminance should reach 500–750 lux to support accurate visual work.
Plumbing systems must accommodate equipment cooling water and emergency eyewash stations. Designers should select corrosion-resistant, easy-to-clean wall and floor materials and use coved corners to eliminate dust accumulation.
Finally, laboratories must install safety facilities—including emergency showers, eyewash units, fire protection systems, and chemical spill response kits—in strict accordance with applicable regulations and inspection requirements.
04 Process Integration
Optimizing Workflow Coordination Across the Three Zones
To function efficiently, a pathology laboratory must operate as a highly controlled production line.
After grossing, staff should transfer specimens to the tissue processing and embedding room through dedicated pass-through windows or enclosed transfer corridors. This approach minimizes manual contact and reduces exposure risks.
Once dehydration is complete, technicians must clearly label tissue blocks and transport them in standardized containers along fixed routes to the sectioning room. At each handover point, staff should perform verification checks to ensure specimen identification accuracy.
Meanwhile, designers should separate personnel circulation paths from specimen transport routes wherever possible. They must also strictly distinguish clean logistics from contaminated logistics.
By implementing a laboratory information system (LIS), facilities can track specimen movement in real time and achieve full-process traceability.
Conclusion
In a well-designed pathology laboratory, precision instruments operate quietly as grossing, dehydration, embedding, and sectioning proceed in a controlled sequence. As a result, technicians produce diagnostic slides that meet the highest quality standards.
Ultimately, advanced diagnostic capability begins with fundamental engineering design. While specimens move through the laboratory, invisible elements—spatial planning, airflow organization, and equipment layout—actively support diagnostic accuracy by guiding every step along a stable and reliable path.