Legionella – Respiratory PCR and Culture

Consistent with O. Reg. 671/92 of the French Language Services Act, laboratory testing information on this page is only available in English because it is scientific or technical in nature and is for use only by qualified health care providers and not by members of the public.

*Uncontrolled print copy. Valid only on day of print: 09 Dec 2023.

Testing Indications

Contact your local Public Health Unit if you suspect an outbreak of Legionella in your facility.

Specimen Collection and Handling

Specimen Requirements

Test Requested	Required Requisition(s)	Specimen Type	Minimum Volume	Collection Kit
Legionella PCR +/- Culture	General Test Requisition	Lower respiratory tract specimens such as BAL, bronchial wash, lung tissues, pleural fluid, sputum, etc. collected during the acute phase of illness.	1 ml for liquid specimen	Sterile container

Submission and Collection Notes

Indicate symptoms and date of onset on the General Test Requisition Form if diagnostic testing is required.

Timing of Specimen Collection

Specimens should be collected during the acute phase of illness.

Limitations

The Legionella species PCR has been shown to cross react with Stenotrophomonas maltophilia. No such cross reaction has been found with the L. pneumophila specific target. Results should be interpreted in the clinical context of the patient.

Storage and Transport

Label the specimen container with the patient’s full name, date of collection and one other unique identifier such as the patient’s date of birth or Health Card Number. Failure to provide this information may result in rejection or testing delay.

Special Instructions

Specimens should be stored at 2-8°C following collection and shipped to PHO laboratory on ice packs.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

The Legionella PCR and culture are performed daily, Monday to Friday.

Turnaround time is up to 4 days from receipt by PHO laboratory for PCR.

Turnaround time is up to 15 days from receipt by PHO laboratory for culture.

Test Methods

Legionella specimens are tested for Legionella pneumophila and Legionella species by PCR. All specimens that test positive by PCR are cultured. Culture positive specimens are identified to the genus, species and serogroup levels.

Interpretation

Negative Result: Legionella species including Legionella pneumophila NOT DETECTED.
Positive Result: Legionella pneumophila DETECTED or Legionella species DETECTED, not Legionella pneumophila.

Reporting

Results are reported to the ordering physician or health care provider as indicated on the requisition.

Specimens that are positive for Legionella are to be reported to the Medical Officer of Health as per Health Protection and Promotion Act.

References

Lab SD 084 – Legionella – Change in testing methodology to Real‐Time PCR Testing