Referral of specimens for confirmation of Legionnaires' disease
Updated 30 October 2025
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Primary diagnosis of Legionnaires’ disease needs confirmation to exclude false positives and typing data should be obtained to assist identification of the possible environmental source.
The Respiratory and Vaccine Preventable Bacteria Reference Unit (RVPBRU), UKHSA, Colindale provides a confirmatory and typing service for Legionella.
For patients with a positive Legionella urine antigen, please send the urine plus a lower respiratory tract (LRT) specimen. Laboratories performing Legionella pneumophila or Legionella spp. polymerase chain reaction (PCR) should also forward PCR positive respiratory specimens (regardless of urine result). Confirmation of diagnosis and typing these samples are offered free of charge.
Primary diagnostic testing is not routinely offered. In exceptional cases or suspected outbreaks, please contact RVPBRU (rvpbruqueries@ukhsa.gov.uk) to discuss before sending samples.
Submit samples to RVPBRU together with Request Form R1.
For further information refer to BRD user manual.
Clinical sample referrals
Specimen: urine
At least 1 ml tested Legionella antigen positive or equivocal by local hospital.
Sampling time:
- within 2 days of admission optimal (up to 10 days recommended)
UKHSA receiving lab:
- RVPBRU
Tests performed:
- detection of Legionella urinary antigen using BINAX EIA
Specimen: LRT
Such as sputum or BAL.
Sampling time:
- within 2 days of admission optimal (up to 10 days recommended)
UKHSA receiving lab:
- RVPBRU
Tests performed:
- in-house real time PCR, culture and typing
Optimal combination
Where possible, simultaneously refer paired urine and LRT specimen.
Specimen: post-mortem LRT sample
Such as lung tissue.
Sampling time:
- as soon as possible after death
UKHSA receiving lab:
- RVPBRU
Tests performed:
- in-house real time PCR, culture and typing
Specimen: presumptive Legionella spp. isolates
Dense suspension in sterile distilled H2O (contained in 2mL tube with ‘O-ring’) or pure culture (subbed on BCYE slope).
Note: agar plates are not suitable “primary containers” for shipping bacterial pathogens.
Sampling time:
- as soon as possible after isolation
UKHSA receiving lab:
- RVPBRU
Tests performed:
- confirmation of identification and typing
Note: Legionella Serology is not performed by RVPBRU.
Water and environmental sample referrals
LD cluster or outbreak investigation only following agreement with HPT, regional (food, water and environmental) FWE Labs and RVPBRU.
Specimen: Water (1 litre) and swab (with transport medium)
Sampling time:
- as soon as possible post-infection
UKHSA receiving lab:
- FWE regional labs
Tests performed:
- culture (isolates referred to RVPBRU for typing)
Water concentrate and swab (with transport medium)
Sampling time:
- as soon as possible post-infection
UKHSA receiving lab:
- FWE Porton via FWE regional laboratories
Tests performed:
- real time PCR
Specimen transportation
Shipment of Infectious Substances (Cat. A, UN2814 or UN2900) and Biological Specimens (Cat. B, UN3373) must comply with relevant guidelines.