In Focus

UK Acceptance for Pseudomonas Testing in Pools and Spas

IDEXX announces the Pseudalert® test for 24-hour detection of Pseudomonas aeruginosa (P. aeruginosa) has been accepted by the UK’s Standing Committee of Analysts (SCA) for analysing samples from pools and spas.
 Christy747 :

IDEXX announces the Pseudalert® test, for 24-hour detection of Pseudomonas aeruginosa (P. aeruginosa) has been accepted by the UK’s Standing Committee of Analysts (SCA) for analysing samples from pools and spas, and is now specified as a recommended method in the Committee’s “blue book” publication1 of “The Microbiology of Recreational and Environmental Waters: Part 7 - Methods for the isolation and enumeration of Aeromonas and Pseudomonas aeruginosa.”

The acceptance follows extensive comparison studies with membrane filtration methods, which have been published in the peer-reviewed journal, Current Microbiology.2 P. aeruginosa is the major Pseudomonas species known to cause health issues and subsequently regulations and guidance in many countries apply specifically to P. aeruginosa detection.

“Pseudalert is an effective test which detects P. aeruginosa quickly, enabling users to safeguard against ‘hot-tub rash,’ otherwise known as hot tub folliculitis and a host of other infections, avoiding illness risk in sensitive populations,” commented Andrew Headland, Senior Business Manager, for IDEXX EMEA. “Its inclusion in the ‘blue book’ is an important step as we look to gain acceptance from public health authorities in further European markets.”

This is the latest acceptance for Pseudalert, which is also approved as an alternative method for P. aeruginosa testing in drinking water and pool water by the German Federal Environment Agency (UBA)3, and was granted the NF Validation4 certification for the testing of drinking water, including bottled water and pool water in France in 2016.

Together with Pseudalert, other IDEXX water tests are now specified as recommended methods by the SCA for recreational and environmental waters, including Colilert®-18 for the rapid detection of coliforms and Escherichia coli, and Enterolert®-E for the isolation and enumeration of enterococci; parts 3 and 4 of the MoREW respectively.

Consistent with other IDEXX Water tests, Pseudalert is simple to use, delivers definitive results with no additional confirmation steps, while minimising the risk of false positives from non-target organisms.

Launched in 2011, the IDEXX Pseudalert test is based on a bacterial enzyme detection technology that signals the presence of P. aeruginosa through the hydrolysis of a substrate in the Pseudalert reagent. P. aeruginosa cells rapidly grow and reproduce using the rich supply of amino acids, vitamins and other nutrients present in the Pseudalert reagent. Actively growing strains of P. aeruginosa have an enzyme that metabolises the substrate in the reagent to produce blue fluorescence under ultraviolet light.

Where quantification of a sample is required, IDEXX has developed a simple device known as a Quanti-Tray®, which consists of 51 individually sealable cells. The Quanti-Tray can also be incubated for 24 hours after which the fluorescent cells can be counted and quantified by reference to a Most Probable Number (MPN) table.

Pseudalert detects P. aeruginosa at 1 CFU in either 100-ml or 250-ml water samples, and gives a confirmed result within 24 hours.



  2. Sartory D et al, Evaluation of the Pseudalert®/Quanti-Tray® MPN Test for the Rapid Enumeration of Pseudomonas aeruginosa in Swimming Pool and Spa Pool Waters, Curr Microbiol. 2015 Dec; 71(6):699-705

  3. Link




About IDEXX Water

IDEXX Water is a global provider of water testing solutions that deliver easy, rapid, accurate and cost-effective information on water quality to laboratories and public utilities around the world. IDEXX entered the water testing market in 1993 with Colilert®, now one of the most frequently used testing methods for the detection of coliforms and E. coli in water worldwide. More recently, IDEXX launched Pseudalert® for 24-hour detection of Pseudomonas aeruginosa in hospital water systems, pools, spas and bottled water. The Pseudalert® Test detects P. aeruginosa quickly to help safeguard against infections in sensitive populations. For more information, visit:

IDEXX Laboratories

About IDEXX Laboratories

IDEXX Laboratories, Inc. is a leader in pet healthcare innovation, serving practicing veterinarians around the more economically successful practices. IDEXX is also a worldwide leader in providing livestock and poultry diagnostic tests and tests for the quality and safety of water and milk. Headquartered in Maine, IDEXX Laboratories employs more than 5,000 people and offers products to customers in over 100 countries. Visit

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