Legionella – Serum Antibody
|Test Requested||Required Requisition(s)||Specimen Type||Minimum Volume||Collection Kit|
Legionella – Serum antibody
Whole blood or serum
5.0 ml blood or 1.0 ml serum
Blood, clotted – vacutainer tubes SST1
Timing of Specimen Collection
Acute phase (within 1 week before or after onset)
Convalescent phase (3-6 weeks after onset)
Haemolysed, icteric, lipemic or microbially contaminated sera or plasma will not be tested.
Preparation Prior to 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.
Centrifuge if using SST.
Specimens should be stored at 2-8°C following collection and shipped to PHO laboratory on ice packs.
Test Frequency and Turnaround Time (TAT)
The Legionella serum antibody testing is performed once weekly.
Turnaround time is up to 5 days from receipt by PHO laboratory.
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 Medical Officer of Health as per the Health Protection and Promotion Act.
An indirect Fluorescent Antibody (IFA) test is used to measure seroconversion, if present.
A four-fold seroconversion to 1:128 indicates recent infection while a standing titre of >=1:256 may indicate infection at some undetermined time.
The IFA is >80% sensitive and >90% specific.