Endoscopy / CSSD


HTM 01-06 Management and Decontamination of Flexible Endoscopes requires hospitals to test the final rinse water from their endoscope washer disinfectors on a weekly basis, this ensures a rapid response to emerging problems of deteriorating water quality.  Weekly water testing includes a Total Viable Count (TVC) by membrane filtration, hardness, and electrical conductivity.  In addition to these tests, clients can also test for Pseudomonas aeruginosa, pH and appearance. As part of the TVC analysis, any positive counts have basic microscopy performed on the colonies, providing a basic indication of the type of bacteria present. This indication can assist infection control with their risk assessments for the safe use of the machine.

20/30 Labs provide customers with between four and six weeks’ worth of kits in advance; this ensures our customers always have kits available should retests be required. Our customers can choose a suitable day of the week from Monday – Thursday (Fridays are available for retests/breakdowns) to perform their testing and the 20/30 Labs courier service will collect samples and bring them back to the lab for analysis. Refer to our logistics page for more information.

Performance Qualification Testing

HTM 01-06 Management and Decontamination of Flexible Endoscopes requires endoscope washer disinfectors to be tested quarterly and annually in addition to the weekly water testing. This is usually performed by the site’s service provider (manufacturer/third party provider).

The following tests are included as part of the quarterly and annual requirements:

  • Total Viable Count (TVC)
  • Pseudomonas aeruginosa
  • Conductivity, hardness, pH and appearance
  • Total Organic Carbon (TOC)
  • Environmental Mycobacteria
  • Surrogate devices (annual requirement only)

CESC Testing (Controlled Endoscope Storage Cabinets)

HTM 01-06 Management and Decontamination of Flexible Endoscopes requires sites to perform quarterly and annual validations on their cabinets. This can be done by the site directly but is normally performed by their service provider (manufacturer/third party) at the same time as the non-microbiological tests are done.

The following tests are included as part of the quarterly and annual requirements:

  • Contact Plates
  • Dryness testing
  • Sterile Lumen Device (annual requirement only)
  • Settle Plates (annual requirement only)

HTM 01-01 Part C

This part of the standard refers to sterilisers. This set of tests is an annual requirement and is usually performed by the site’s third-party service provider, as specialist equipment is required to extract the steam to enable us to analyse the water.

Tests include:

  • Endotoxins
  • Chemical suite (list)

HTM 01-01 Part D

This part of the standard refers to instrument washer disinfectors. This set of tests is an annual requirement and is usually performed by the site’s third-party service provider.

Tests include:

  • Total Viable Count (TVC)
  • Endotoxins
  • Chemical suite (list)

Potable Water Services

Total Viable Count (TVC) by pour plate 

Total viable count (TVC) is a valuable trend analysis tool for monitoring the overall microbial quality of a water supply. It is a quantitative test that can determine the number of viable microorganisms present in a water sample but is unable to identify individual species.

Potable water, spa, pool and hydrotherapy water, and cooling tower water should be routinely monitored using TVC. Unlike endoscopy waters that undergo TVC by membrane filtration, potable water is cultured on pour plates. This involves combining the water sample with liquified Yeast Extract Agar (YEA) which is then allowed to set, before being incubated for between 24 and 72 hours depending on the water type.

Renal dialysis water should also be routinely tested by TVC; click here for more information on Renal Testing.

Legionella Analysis

Under the Health & Safety at Work Act 1974, there is a duty of care in the UK to perform routine analysis of water samples for the presence of Legionella, a group of organisms that cause pneumonia-like illnesses particularly in those that are elderly or immunocompromised.

The Health & Safety Executive (HSE) has published ‘The Approved Code of Practice: Legionnaires’ disease: The control of Legionella bacteria in water systems (L8)’; this is a practical guide for employers to help them manage and control the risks in their water systems.

20/30 Labs customers include water treatment companies, plumbers, care homes, schools, and gyms, to name just a few. Legionella analysis involves membrane filtration of samples onto selective buffered charcoal yeast extract (BCYE) agar followed by 10 days of incubation. Interim results are available at 4, 7 and 10 days. As part of the analysis we also identify the serogroup to assist sites with their risk assessments.

20/30 Labs is registered with the Legionella Control Association for Analytical Services and are a UKAS accredited laboratory (4236) for the detection and enumeration of Legionella in rinse, reverse osmosis, potable, spa, swimming pool and hydrotherapy pool waters.

Pseudomonas Analysis

Pseudomonas aeruginosa is a common environmental bacterium typically found in soil and water. To the majority of people it is harmless, however in the healthcare setting it is a clinically important opportunistic pathogen that must be controlled in hospitals due to its propensity to infect the immunocompromised and cause nosocomial, or healthcare-acquired, infections (HAIs).

HTM 04-01 Safe Water in Healthcare Premises and HTM 01-06 Management and Decontamination of Flexible Endoscopes detail the requirements for the sampling, methods of analysis and remediation of Pseudomonas aeruginosa in water in various settings including healthcare establishments and public buildings.

Analysis involves the membrane filtration of samples onto selective Pseudomonas CN supplemented agar follow by 48 hours incubation. Confirmation is carried out using Milk Cetrimide agar for casein hydrolysis and pyocyanin production with a further incubation period of 24 hours.

Escherichia coli and coliform analysis

Tests for coliform bacteria and Escherichia coli (E. coli) are the most important routine microbiological examinations carried out on drinking water. These tests provide a sensitive means for detecting faecal contamination, for assessing raw water quality, the effectiveness of water treatment and disinfection, and for monitoring the quality of potable water in distribution.

E. coli and coliform analysis is performed by membrane filtration onto selective Membrane Lactose Glucuronide Agar (MLGA) followed by an incubation period of 18 hours.

Cleanroom Validation


Areas for which environmental cleanliness is of paramount importance, such as operating theatres, instrument reprocessing cleanrooms and pharmaceutical manufacturing cleanrooms are subject to regular monitoring and validation activities. 

These areas should be routinely sampled in accordance with the requirements of BS EN ISO 14644 and BS EN ISO 14698, which include testing for effective air filtration through air particle counting and testing for environmental flora through contact plates, settle plates and personnel monitoring.

ISO 14644 establishes the classification of air cleanliness in cleanrooms and controlled environments.

ISO 14698 describes the principles and basic methodology to assess and control biocontamination where cleanroom technology is applied, in order that biocontamination in zones at risk can be monitored in a reproducible way and appropriate control measures can be implemented.

20/30 Labs Limited can perform the required analysis for cleanroom validation and the consumables and testing equipment required to perform the testing.

Airborne Particulate Counts

ISO 14644 Cleanrooms and Associated Controlled Environments specifies the classification of air cleanliness in terms of concentration of airborne particles in cleanrooms and other controlled environments. Cleanrooms are classified in an 8-tier system, with class 1 cleanrooms being the most particle-free and class 8 cleanrooms allowing the most particles. Hospital cleanrooms are class 8, but they must still be routinely tested to demonstrate the suitability of the area for medical device processing.

A 20/30 Labs technician can attend your site to conduct particulate counts and classify your cleanroom according to ISO 14644. Our particle counters are regularly serviced and UKAS-calibrated to ensure optimum performance and confidence in results.

In addition to particulate counts, we can also measure pressure differentials between your cleanroom and adjacent rooms, measure air flow within the room and calculate the number of air changes per hour.


The da Vinci surgical system, developed and manufactured by Intuitive, is a robotic surgical system designed to optimise patient outcomes by facilitating minimally invasive surgery (MIS) over higher risk open surgical procedures.

As one of the first robotic assisted, minimally invasive surgical systems to be approved by the Food and Drug Administration (FDA) in 2000, the da Vinci system has continued to innovate and there are now almost 5000 units in use across 67 countries.

20/30 Labs has been recognised by Intuitive as having the technical expertise and industry experience to perform validations, residual protein testing and bioburden testing on these highly specialised surgical instruments.

Environmental Monitoring

ISO 14698 Cleanrooms and Associated Controlled Environments – Biocontamination Control describes the basic methodology to assess and control biocontamination in cleanrooms, including active air sampling, contact plates and settle plates. Areas at risk of biocontamination can be routinely monitored using these methods in a reproducible manner, allowing for trend analysis over time and enabling appropriate control measures to be implemented.

Contact Plates

Contact plates are used to measure microbial contamination of work surfaces. The surface of an agar plate is pressed against a flat sampling surface to pick up any microorganisms that may have settled onto the location by operator contact or from the environment.

Settle Plates

Settle plates give an indication of airborne microbial contamination. Agar plates are left, uncovered, for a set period. Any airborne microorganisms that settle onto the surface of the agar plate will grow on incubation and give a representative measure of the microorganisms that may deposit onto surfaces and exposed medical devices within a cleanroom.

Active Air Sampling

Active air testing involves extracting a set volume of air within a given environment into a calibrated sampler which is then passed onto the surface on an agar plate. Plates are then incubated to allow the growth of colonies of airborne microbes.


Swabs are used on irregular, uneven surfaces where contact plates cannot otherwise be used. Swabs will be wiped over such surfaces and inserted into a vial of liquid suspension medium that preserves the levels of bacteria present, before being returned to the laboratory for analysis. Swabs provide a reliable way of assessing contamination levels, thus measuring routine cleaning efficiency.

Renal Testing

Dialysis water is water that has been treated to meet the requirements of ISO 13959:2014 Water for haemodialysis and related therapies and which is suitable for use in haemodialysis applications, including the preparation of dialysis fluid, reprocessing of dialysers, and the preparation of concentrates. 

Haemodialysis and haemodiafiltration can expose the patient to more than 500L of water per week. This increased exposure requires control and monitoring of water quality to avoid excess exposure to known or suspected harmful substances or microorganisms.

Standard dialysis fluid is considered as the minimum quality; ultrapure dialysis fluid is recommended for routine haemodialysis and is mandatory for creating on-line prepared substitution fluid. The use of ultrapure dialysis fluid is associated with a range of clinical benefits including lower indices of inflammatory response.

Total Viable Count (TVC)

Total viable count (TVC) is a valuable trend analysis tool for monitoring the overall microbial quality of a water supply. It is a quantitative test that can determine the number of viable microorganisms present in a water sample but is unable to identify individual species.

Standard dialysis fluid is cultured on pour plates; this involves combining the water sample with liquified Tryptone Glucose Extract Agar (TEGA) which then sets to a semi-solid consistency before being incubated. When analysing ultrapure dialysis fluid, we must be able to detect as little as one bacterial cell in 1 ml of sample, so testing is performed by membrane filtration in order to achieve this very high level of detection. Both testing methods require samples to be incubated at 17 to 23°C for 7 days.

Compliance with ISO 13959 Water for haemodialysis and related therapies requires that renal waters be sampled for TVC monthly.

Endotoxin Analysis

Endotoxins are found in Gram-negative bacteria, such as Pseudomonas aeruginosa, E. coli and Neisseria meningitidis. They are comprised of extremely antigenic molecules called lipopolysaccharides (LPS) that provoke a powerful immune response when detected by the immune system. The fever and inflammation generated as the immune cells fight the infection can lead to the onset of septic shock, an often-fatal condition.

Endotoxins are particularly dangerous due to their ability to generate an immune response even when their host bacterium is dead, and the bacterial cell has broken down. The endotoxin test can detect these freely circulating LPS molecules.

20/30 Labs uses the Endosafe PTS system to perform endotoxin testing. This system has been chosen over other endotoxin methods as it offers a rapid and repeatable detection system that can detect endotoxin concentrations below an action level of 0.25 EU/ml in standard dialysis fluid, and below an action level of 0.005 EU/ml in the Ultrapure renal water.

Compliance with ISO 13959 Water for haemodialysis and related therapies requires that renal waters be sampled for endotoxin monthly.

Chemical Analysis

ISO 13959 Water for haemodialysis and related therapies stipulates the maximum allowable levels of toxic chemicals, dialysis fluid electrolytes and other trace elements permitted in renal dialysis water.

20/30 Labs uses the Thermo Scientific™ Gallery™ Plus, a fully automated, high-capacity analyser to provide fast, reproducible results on a suite of chemical tests to ensure full compliance with ISO standards.

ISO 13959 Water for haemodialysis and related therapies requires that renal waters be sampled for chemical analysis on a quarterly basis.

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