How to design a diagnostics lab

Diagnostics labs are one of the most important cogs that support modern healthcare. In the NHS, pathology underpins the majority of clinical pathways; NICE cites NHS England’s estimate that ~95% of clinical pathways depend on access to pathology services, while the Royal College of Pathologists has long noted that around 70% of diagnoses involve laboratory test data.

It is clear to see that this clinical centrality must translate into very specific design obligations to achieve optimal functionality.

Non-negotiables of laboratory design include:

• Protecting sample integrity from order to report (pre-analytical → analytical → post-analytical). The pre-analytical phase remains the biggest risk; multiple studies and audits attribute ~60–70% of lab errors to this stage, driven by collection, identification and transport issues.

• Delivering verified, repeatable turnaround times (TATs) aligned to local and national indicators, for example, cellular pathology programmes commonly target 90% within 7–10 days for cancer pathways, with local bandings monitored monthly.

• Meeting current regulation and accreditation, notably ISO 15189:2022 for quality and competence (with UKAS-led transition and guidance in the UK).

• Implementing risk-based biosafety consistent with WHO’s Laboratory Biosafety Manual (4th ed.) plus discipline-specific standards (e.g., EN 12469 for microbiological safety cabinets).

• Providing healthcare-grade building services, especially ventilation to HTM 03-01 (2021) across applicable areas.

A high-performing diagnostics lab is built around the sample journey. Start with a process map, then translate it into rooms, adjacencies and services. The following “engine room” sequence is a robust baseline for diagnostic laboratory design:

Specimen receipt & accessioning (Grade: clean but not aseptic)

• Direct, segregated access from courier dock; no cross-traffic with staff/visitor flows.

• Pass-through hatch to core lab; barcoded chain of custody embedded in the LIMS.

• Immediate triage to temperature-controlled storage (e.g., 2–8 °C fridges) for time-sensitive assays.

• KPI wallboard for real-time intake volumes and age of unprocessed samples (supports TAT governance).

Why: This is where most controllable pre-analytical risk sits.

Pre-analytics & automation (centrifugation, decap/recap, aliquoting)

• Plan linear “in-one-side/out-the-other” benches, with automation tracks where volumes justify it.

• Provide spill-safe surfaces, eyewashes, and clear service zones for maintenance without halting flow.

• Buffer storage sized to peak hour arrivals (use historical courier profiles).

Why: Automation here reduces error and stabilises TAT at scale.

Waste, decontamination & logistics

• Dirty flows never cross clean; autoclave and clinical waste rooms have independent extract; robust storage for solvents, reagents and cryogens with segregation and bunding.

• Service corridors and removable panels allow equipment swaps without cutting benches.

Analytical cores, each with tailored requirements

• Buffer storage sized to peak hour arrivals (use historical courier profiles). Why: automation here reduces error and stabilises TAT at scale.

• Blood sciences (biochemistry/haematology/immuno): high-throughput analysers, clean utilities, UPS; visibility from control desk for exception handling.

• Microbiology/virology: containment zoning, Class II MSCs to EN 12469, negative pressure where risk assessed, separated clean/dirty corridors, and autoclave back-of-house routes.

• Molecular diagnostics/genomics: unidirectional flow (pre-PCR → PCR setup → post-PCR), pressure cascades, anti-contamination protocols, and environmental monitoring.

• Cellular pathology (histology/cytology): dedicated formalin/solvent storage with ventilation per risk assessment, tissue processors, cryostats, and digitisation rooms for slide scanners (acoustic and thermal control).

Why: Each discipline has different bio-risk, vibration, temperature, and cleanability needs; the plan must reflect this.

Results, reporting & MDT zones

• Daylit write-up spaces adjacent to (but acoustically isolated from) analytical areas.

• Secure telemedicine suites for multi-disciplinary team (MDT) boards; camera-first layouts with AVIXA display sizing and lighting good enough for on-screen micrographs.

Waste, decontamination & logistics

• Dirty flows never cross clean; autoclave and clinical waste rooms have independent extract; robust storage for solvents, reagents and cryogens with segregation and bunding.

• Service corridors and removable panels allow equipment swaps without cutting benches.

UK healthcare-specific overlays:

• For hospital-based pathology hubs and spokes, consult HBN 15 for planning principles, and local equivalents (e.g., NHS Scotland’s HBN 15 publication) for networked service design.

• Apply HTM 03-01 to laboratory spaces that require specialised ventilation; coordinate with infection prevention teams via formal risk assessment.

1) Accreditation and quality management by design

• Align the facility QMS to ISO 15189:2022 from day one, documented risk management, metrological traceability, data integrity, POCT oversight, and contingency planning (power, IT, reagent shortages). UKAS provides transition guidance and expectations.

2) Biosafety and containment zoning

• Adopt a risk-based model (WHO LBM 4th ed.) rather than a one-size-fits-all approach. For procedures generating aerosols with Risk Group organisms, specify Class II MSCs to EN 12469 and pressure regimes that prevent escape from “dirty” rooms.

3) Ventilation and environmental control

• Use HTM 03-01 (2021) for design/operation; agree temperature/humidity bands per discipline (e.g., micro/virology cooler and under negative pressure; histology solvent areas with targeted extract). Commission with verifiable air change rates and pressure logs.

4) Human-centred environments that still perform

• Lighting: glare-controlled, high-CRI task lighting for bench work; vertical illuminance for digital microscopy rooms to reduce eye strain.

• Ergonomics: bench heights, seated/standing alternation, and reach distances designed around critical tasks (microtomy, pipetting, scanner loading).

• Wellbeing: daylight to write-up areas, rest spaces away from solvents and noise. (These “soft” factors support accuracy and retention.)

5) Digital enablement and data integrity

• LIMS at the core; interoperability with hospital EPR and image management (digital pathology/PACS) to speed MDTs. NHS case studies underscore how TAT improvements depend on process plus digital, not just extra equipment.

6) Capacity modelling and diagnostics networks

• England’s network model (hub-and-spoke across 29 pathology networks) assumes specimen transport at scale, local rapid-response spokes, and consolidated specialist hubs. Your plan should reflect that logistics truth (dock sizing, courier routes, redundant fridges).

1. ISO 15189:2022: clauses mapped to rooms, processes and SOPs; evidence path for UKAS.

2. WHO LBM 4th ed: risk assessment on all biological activities; cabinet classes specified to EN 12469.

3. HTM 03-01 (2021): pressure cascades, ACH, alarms; Part A (design) and Part B (operation).

4. HBN 15 Pathology: room lists, flows and adjacencies for hospital-based labs (plus devolved nation variants).

5. Pre-analytical risk controls: mis-labelling defences, temperature logging from receipt, and spill/needle-stick provisions because that’s where most errors hide.

How much area per person is typical in diagnostics labs?

It varies with discipline and automation density, but as a planning start point many UK projects allow 10–15 m² per lab user in general diagnostics, rising with high-containment or heavy equipment. The final figure should be derived from your room list, throughput model and equipment clearances (see HBN 15 for NHS contexts).

We’re moving to ISO 15189:2022, what should change in the facility brief?

Bake in risk-based thinking (sample journey hazards, environmental monitoring), data integrity, POCT oversight, and business continuity (power/IT). UKAS has specific transition guidance worth citing in your quality plan.

What’s the evidence that pre-analytics dominates error rates?

Multiple reviews and UK audits find ~60–70% of lab errors occur before analysis, collection, labelling, transport, and preparation, strengthening the case for investment in receipt areas, automation and training.

Are national TAT benchmarks uniform?

Not completely. Cellular pathology programmes often target 90% ≤7 days / 95% ≤10 days for cancer pathways; several trusts now publish local bandings and NHS dashboards track assurance. Design for capacity and visibility to hit these.