Cleanroom Validations and Microbiological Analysis

Date Published: 15 May 2023

Written by: Farzana Sultana

Cleanrooms and associated controlled environments provide for the control of airborne contamination to levels appropriate for accomplishing contamination-sensitive activities such as medical device sterilisation. A cleanroom is constructed in a manner to minimise the introduction, generation, and retention of particles inside the room. Sampling falls under harmonised standards BS EN ISO 14644: Cleanrooms and associated controlled environments and BS EN ISO 14698: Cleanrooms and associated controlled environments — Biocontamination control.


Figure 1:

20/30 Labs are industry leaders in environmental sampling, we can offer expert technical advice, explain the impact of the results to the environment and the processes occurring, and help manage contamination events. We have a team of CTCB-I trained field technicians who can map, assess, and test cleanrooms and theatres. All 20/30 Lab methods for environmental sampling are UKAS accredited, routinely audited, and supported by external proficiency qualifications.


  • Stage 1 : Protocol

    Sampling will is undertaken at the frequencies and locations specified by the client (excluding where guidance provides the sampling regime e.g., ISO 14644), against a service level agreement. The service level agreement outlines sampling types; this can be just based on cleanroom operation or the performance qualification of equipment within the department (cleanroom, trolleys, detergents/soaps, potable water, endoscopes, instrument washer disinfectors as per HTM 01-01 Part D, steam sterilisers as per HTM 01-01 part C, endoscope washer disinfector as per HTM 01-06), test parameters (air particulate count, air monitoring, settle plates, contact plates, finger imprints, swabs, medical device sterility, medical device bioburden, total viable count by pour plate, total viable count by membrane filtration, selective testing for E. coli/ coliform or P. aeruginosa, endoscope flush tests), frequency (monthly, quarterly, annually) and quantity.

    The client may have specific alert and actions levels for certain tests.

    Method statements are provided for each test.


  • Stage 2 : Cleanroom Testing

    Arranging a site visit

    After the onboarding of a client and the agreement of service and testing schedule. An initial site visit is carried out, allowing extra time, to locate each cleanroom site, map the room(s) and understand where to gown up, where any unusual sampling locations are (i.e., taps or hatches or RO valves) and where products or medical devices are kept (if they are to be tested).

    Preparing for site visit

    Media and consumables are packed against the testing schedule.

    All equipment packed is checked for calibration status.

    Testing on Site

    Sampling is carried out in the operational state with any process equipment running and personnel performing normal operations. Sampling does not interfere with or compromise the quality of any medical devices being packed.

  • Stage 3 : Lab Testing

    Returning samples and processing

    Samples are handed over to data entry at 20/30 labs, where they are logged in and put in the refrigerator or incubator depending on sample type.

  • Stage 4 : Report

    Test Reports will be issued when microbiological analysis is complete. Customer reports available via a bespoke 20/30 Labs LIMS interface which has a client portal for sample tracking and access to historical data for trend analysis. The reports will contain a comments section to detail and summarise testing that has fallen outside the alert & action levels.


Cleanrooms validated quarterly.


Reports turned around within 12 Days (2022)


Reports turned around within 12 Days (2023 so far)


Pass on External Quality Assessment


Medical Devices Tested (2022)

20/30 Labs have a wealth of experience in cleanroom and microbiological testing. We are UKAS accredited for the sampling and enumerating of environmental samples. We have specialised calibrated equipment (such as 0.1-5µm Airborne Particle Counters, Air samplers, Balometers and Manometers) that ensure all results are accurate and reliable. We have capability to test anywhere, nationwide.

Our microbiological expertise means we not only enumerate the samples, but we also provide an idea of the colonies present in the sample. We have MALDI-TOF capability, which enables us to identify the specific species of organism present on the plates. We make sure to be aware of every client’s action and alert limits, and comment if they fall outside of this, on every report.


By providing cleanroom testing, 20/30 Labs is able to over a 360° experience in sterile service and endoscopy departments. We are UKAS accredited for all critical processes:

  • Weekly water testing for Endoscope washer disinfector (EWD)
  • Selective testing for aeruginosa and Mycobacterium spp.
  • ISO 15883-5: 2021 Compliant Test Soil
  • Quarterly PQ (Performance Qualification) of EWD, as per HTM 01-06
  • Annual PQ (Performance Qualification) of EWD, including surrogate device and biofilm testing, as per HTM 01-06
  • Dry Cabinet Testing as per EN 16442
  • Endoscope Flushing/Swabbing (Bioburden)
  • Endoscope Storage Cabinet Testing
  • Potable water testing
  • Including selective testing for coli, P. aeruginosa, Enterococci spp.
  • Quantitative Residual Protein Analysis
  • Endotoxin Analysis
  • Chemical Analysis, as per HTM 01-01 Part C and HTM 01-01 Part D
  • Medical Device Bioburden
  • Medical Device Sterility


  • BS EN ISO 14644: Cleanrooms and associated controlled environments (part 1 – 3)
  • BS EN ISO 14698: Cleanrooms and associated controlled environments — Biocontamination control.
  • ISO 15883 Washer-disinfectors, General requirements (Part 2 and 4)
  • Health Technical Memorandum 01-01: Management and decontamination of surgical instruments (medical devices) used in acute care Part D: Washer-disinfectors
  • Health Technical Memorandum 01-01: Management and decontamination of surgical instruments (medical devices) used in acute care Part C: Steam sterilization
  • Health Technical Memorandum 01-06: Decontamination of flexible endoscopes Part D: Validation and verification (including storage/drying cabinets)
  • AAMI TIR 12: 2020 Designing, testing, and labelling reusable medical devices for reprocessing in health care facilities: A guide for medical device manufacturers.
  • AAMI ST98: 2022 Cleaning validation of health care products—Requirements for development and validation of a cleaning process for medical devices.
  • Food and Drug Administration “Reprocessing Medical Devices in Health Care Settings Validation Methods and Labelling”
  • ISO 17664:2017 Processing of health care products - Information to be provided by the medical device manufacturer for the processing of medical devices
  • ISO 17665-1:2006(E) – Annex D: Sterilization of health care products - Moist heat - Part 1: Requirements for the development, validation and routine control of a sterilization process for medical devices
  • AAMI ST79: 2017 Comprehensive guide to steam sterilization and sterility assurance in health care facilities
  • ISO 14937:2009 Sterilization of health care products — General requirements for characterization of a sterilizing agent and the development, validation and routine control of a sterilization process for medical devices
  • BS EN ISO 11737-1:2018 +A1:2021 Determination of a population of microorganisms on products
  • BS EN ISO 11737-2:2020 Determination of a medical device sterility