Environmental Legionella Isolation Techniques Evaluation Program

New! Update on Alternative Test Methods

CDC and the Wisconsin State Laboratory of Hygieneexternal icon (WSLH) are exploring ways to make the ELITE Program more responsive to member laboratories’ needs. CDC and WSLH are aware of the growing popularity of alternative test methods that may be more applicable to routine testing than traditional spread-plate culture methods. For 2018, the ELITE Program is planning to add additional performance evaluation criteria to its reports. This will allow regional, national, and international accrediting bodies to evaluate your laboratory in a variety of detection methods, including PCR and bacterial enzyme detection. Please check back for updates.

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Although Legionella lives in a wide variety of freshwater habitats, it can be difficult to isolate. The Environmental Legionella Isolation Techniques Evaluation (ELITE) Program was created as a way for laboratories to test their Legionella isolation techniques against standardized samples.

ELITE Application Website

Visit the ELITE application website to view a list of laboratories that have earned a certificate to be an ELITE member and to enroll as a new member in the program. Current members can also enter test results and receive their certificates through the website. A few areas of the ELITE application website are password protected for members only.

Frequently Asked Questions

Elite program logo.

Q: What does the ELITE certificate mean?

A: The ELITE Program identifies laboratories that are able to isolate (grow and identify) Legionella from a water sample using a culture method. Earning an ELITE Certificate does not guarantee that at other times a laboratory will be able to isolate legionellae from every sample in which they are present, because the ability to find Legionella in a sample can be affected by the quality of the sample the laboratory receives.

Q: How does the program work?

A: Participating laboratories receive two panels of unknown samples each year. Laboratories that correctly identify which samples contain culturable Legionella, in both panels, earn a Certificate. Participating laboratories are publically listed as an ELITE Member. ELITE Members are evaluated annually. ELITE samples may also be suitable to evaluate non-traditional detection methods such as PCR or bacterial enzyme detection. However, only culture results are considered by the ELITE Program.

Q: Who can participate?

A: Any laboratory that performs culture of environmental samples for Legionella can participate in the ELITE Program. Although most laboratories that participate are commercial, some may be affiliated with a university or public health department. Commercial companies with more than one laboratory location must register each individual location.

Q: What does it mean if the lab I am using is not on the ELITE Members List?

A: It depends on the reason for testing environmental samples for the presence of Legionella. If you need samples tested during an investigation into cases of disease, you should consider using an ELITE member laboratory. This will ensure that the laboratory understands the extra measures needed to secure an environmental isolate for public health investigations. However, when testing is used to validate a water management program in the absence of disease, different performance criteria may apply. Regardless of the reasons for testing, assays should be conducted by a laboratory that is accredited by a regional, national, or international accrediting body. Also, the test method used for finding Legionella should be included in that laboratory’s scope of accreditation.

Q: Can ELITE Members provide Legionella water management programs and remediation services?

A: Although some groups will provide water management consultation and other services in addition to water testing, these services are beyond the scope of the ELITE Program. The ELITE Program only assesses laboratories in their ability to isolate culturable Legionella from water samples. The ELITE Program does not assess the ability to manage building water systems or eliminate Legionella from them. Testing for Legionella may be part of a site-specific, comprehensive building water system management program. See CDC’s Practical Guide to Implementing Industry Standards pdf icon[36 pages, 13.30 MB] for more details.

Q: Why does CDC offer the ELITE Program?

A: Investigating cases and outbreaks of Legionnaires’ disease often requires comparing Legionella (bacteria that cause Legionnaires’ disease) isolates grown from patient samples to Legionella from environmental (water) samples. However, finding Legionella among the many different microorganisms present in the environment can be difficult. Also, whoever is testing the samples may use different procedures for collection, transport, and storage of samples and isolates, which could affect the chances of finding Legionella in a sample. CDC created the ELITE Program in order to identify laboratories that isolate Legionella from environmental samples. These laboratories can be helpful during public health investigations. As a service to the general public and public health partners, CDC maintains a publically accessible Member’s List of laboratories that perform Legionella testing.


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