qPCR is an accepted Legionella testing technology


The Association of Water Technologies (AWT) is an international water treatment association representing over 500 companies that specialize in applying water treatments for industrial and commercial cooling and heating systems.

In 2019, AWT released a Legionella position statement and guidance document that states: “PCR testing is useful for negative screening of microbial samples for Legionella, especially when used in conjunction with culture methods.”

This position statement is consistent with hundreds of research studies which have found Legionella qPCR testing is the most sensitive technology for detecting Legionella contamination. In other words, if a Legionella qPCR test is negative, then there is minimal risk.

AWT’s document also describes limitations of qPCR:

  • “GUs [Genomic Units] cannot be equated with CFUs [Colony Forming Units].”
  • “PCR methods are limited because viable organisms that may be able to cause infection cannot be differentiated from nonviable Legionella.”
  • “Inability to discriminate between strains”
  • “cross-reaction with non-Legionella bacteria (i.e., a false positive result)”
  • “chemicals in the sample that inhibit the PCR reagents”

Note that Genomadix’s on-site Legionella qPCR test has proprietary technology that solves all of these traditional limitations of qPCR testing:

  • Genomadix’s test is calibrated so that 1 GU with Genomadix is equal to 1 CFU with culture (this means you can use your existing action levels)
  • Genomadix’s test has proprietary technology that detects viable Legionella bacteria and not nonviable cells
  • Genomadix’s test discriminates between pathogenic Legionella pneumophila serogroups vs. other strains
  • Genomadix’s test is validated according to ISO 12869 to not cross-react with non-Legionella bacteria (i.e., no false positive results)
  • Genomadix’s test has a positive internal control that detects whether there are PCR-inhibitory chemicals in the sample

Overall, Genomadix’s on-site Legionella qPCR test is the fastest and most accurate method for detecting Legionella contamination. It is the 2018 winner of the HVAC industry’s top innovation award for Indoor Air Quality (IAQ). Customers include Legionella public health experts and leading companies in real estate, data centers, and healthcare.

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