Legionella Self-Testing 

]If you are responsible for managing water systems in your business, you will know that there is a legal duty to control risks associated with Legionella bacteria. In many countries, under Health and Safety regulation, you are responsible for ensuring the safety of your employees, customers and the general public.

No matter what industry you are in you will be expected to carry out a Legionella Risk Assessment and ensure that a water management plan is in place. Legionella risk assessment is an essential management procedure. It involves careful examination of the risks inherent in man-made water systems, to identify and assess the possibility of Legionella exposure.

The responsible person (often called the duty holder) should be familiar with the water system, and any associated equipment, in order to understand whether the system is likely to harbor any risk. A simple risk assessment of a domestic property may indicate that the risks are low and no further action is needed, while more complex systems may have risks that need further action.

Legionella testing is a standard part of controlling, monitoring and assessing risk in any facility: it checks status and monitors the direct impact that controls, corrective action or out of allowable range events have on Legionella levels. Routine Legionella testing reduces the potential health and legal risks inherent in ignoring this part of Legionella risk assessment.

Traditionally, to test your water for Legionella, you would have to collect the water sample, send it to the laboratory and wait 7-10 days for the results. However, new developments in the latest water testing technologies has allowed scientists to create a new method for detecting Legionella in water. Legionella antigen tests can be performed on-site and provide results almost immediately. The good news is that antigen tests are so easy to conduct that anyone can do it!

Legionella testing Methods 

There are a number of different methods you can use to test your water system for Legionella.

• Lab culture method – traditional method for the detection and quantification of Legionella. The results take 7-10 days because the bacteria must be cultured in an artificial environment. Research shows that limitations of the lab culture test often make the management of water systems difficult and ineffective. 
• qPCR - PCR (Polymerase Chain Reaction) testing is a molecular biology technique in which the DNA of a microorganism is extracted and then amplified. This enables the laboratory to determine the presence and quantity of that organism’s DNA in a water sample. Depending on the sample transportation process, the results can take between 24-48 hours.
• Antigen testing – this method is optimised to quickly detect cell surface Legionella antigens on-site, in environmental water and biofilm samples, and in all phases of the Legionella life cycle. The results are delivered in 25 minutes.

Both, lab culture test and qPcr are carried out in a laboratory, where specialised equipment is available and the team of scientists conduct the test. On the other hand, antigen testing, allows detection of Legionella bacteria on-site, with no special equipment or training.

How does the Legionella rapid antigen test work?

The antigen self-test detects Legionella using well-established lateral flow test technology. The same technology is used to determine if a patient has Legionnaires’ disease in many medical tests. The test works just like a pregnancy test, except it detects Legionella Serogroup 1 antigen rather than pregnancy markers. It works by attaching colour indicators to Legionella antibodies printed on a cellulose strip. 

Can I interpret results myself?

The antigen test provides the user with an easy ‘yes’ or ‘no’ answer about the presence of Legionella in the water system. One line on the test strip indicates a negative result (Legionella not detected) whereas two lines mean a positive result (Legionella detected). The test can also be read and recorded by using the Smartphone reader app, available to download for free from the iStore.

Will I be fully responsible for the Legionella test results?

People often think that conducting a self-test increases their responsibility. They believe that sending the sample to the laboratory or employing third party to test the water system is a way of shifting the responsibility onto someone else. The truth is that as a duty holder you must ensure the safety of your employees and the public. Although following the regulations and guidelines is important, if you fail to take the necessary measures to decrease the risk of Legionella, both you and your organisation will be liable for prosecution.

Failure to implement proper control systems or to carry out frequent risk assessments and testing can lead to outbreaks, heavy fines and huge reputational damage, for organisations, their owners and managers.     

Can the Legionella rapid testing method replace lab culture test?

Rapid antigen testing should not be treated as a replacement for the culture test, because in many industries the laboratory test is still a legal requirement. However, compliance with regulations is the minimum testing that should be carried out on your system. Duty Holders can still be fined and even imprisoned if a death has occurred because of individual negligence.

Taking into consideration the limitations of the culture method, which is the recommended technique for testing Legionella despite its often low and variable accuracy, other reasonable measures must be taken to prevent Legionella outbreaks, even if the law does not require them.

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How can Legionella Antigen test help me to manage water systems more effectively?

• The test provides an immediate picture of Legionella contamination risk, which allows you to make quicker, better- informed decisions about improving water quality.
• The rapid test helps you to maintain high service standards and protects you from reputational damage.
• The test helps to reduce public and employee health risk by minimising the time taken to identify Legionella.
• Recording test information with the Smartphone app while analysing data helps to create a complete picture of Legionella contamination risk and roadmap to prevent future outbreaks.
• Prevention is always better than a cure. By using this simple test, you can save the money and effort it would take to deal with an outbreak of Legionnaires’ disease.
• This responsible approach is not only the right thing to do for the people that spend time in your building, but it is also smart for your organization to protect itself against litigation, huge fines and the resulting reputational damage following an outbreak.