LEGIONELLA, RESPIRATORY, CULTURE - (Resp)

Test Code: LDB

Test Indications:
Legionella spp. are responsible for approximately 3% of community-acquired pneumonia cases in Canada.  Risk factors for infection with Legionella spp. include age ≥50 years, smoking, chronic lung disease, immune system disorders due to disease or medication, systemic malignancy, underlying illness such as diabetes mellitus, renal failure, or hepatic failure, recent travel with an overnight stay outside of the home, and exposure to hot tubs.  Testing for Legionella is indicated in more severely ill patients with community-acquired pneumonia, in patients with pneumonia and specific risk factors for Legionella spp. infection, and in the setting of a possible outbreak.  The treatment regimens for community-acquired pneumonia currently recommended in North America provide empiric coverage against Legionella spp.  When ordering this test, the clinician should carefully consider whether a positive or negative test result will alter clinical management.

Recommendations:
There are strict criteria for testing.  Testing is indicated for inpatients with community-acquired pneumonia and one of the following:
1.1 - ICU with community-acquired pneumonia
1.2 - Active alcohol abuse
1.3 - Travel within the last 2 weeks
1.4 - Pleural effusion
1.5 - Failed therapy
1.6 - Solid organ or hematological transplant patient
 
Failure to indicate at least one of the above testing criteria in the clinical history field of the Shared Health Microbiology Requisition will result in specimen rejection.
 
No more than one specimen every 5 days will be accepted, and no more than 3 per admission without consultation with the site microbiologist on call.
 
Note that testing for other indications not covered above in 1.1 to 1.6 (e.g., suspected community outbreak) may be approved on a case-by-case basis by consulting the site microbiologist on-call..
 
Clearly indicate on the microbiology requisition the specimen site, the specimen type, and the test requested (Legionella Culture).  If additional tests are required on the specimen, these should also be indicated on the requisition.

Patient Preparation Instructions:
Refer to the relevant specimen type (sputum, endotracheal aspirate, bronchial washing, bronchial alveolar lavage, pleural fluid [aerobe (ASP/TISSUE/SWAB)]) for information on patient preparation instructions. 
Accurate patient identification must be made prior to sample collection.  Patient identification should be done in accordance with site policy.
Samples and requisitions must be labeled/completed in accordance with the Shared Health Specimen Acceptance Policy.

_SH Microbiology - Provincial Requisition (R250-10-06)

A descriptive report will be sent.  If Legionella spp. are recovered on culture, this will be reported to the clinician.  If Legionella spp. are not recovered on culture, a report of "No Legionella spp. isolated." will be issued.
Preliminary results are issued as necessary.  In cases where Legionella spp. are not recovered, a final negative result will be issued after 14 days.

Weekdays

Specimen Handling:
Refer to the relevant specimen type (sputum, endotracheal aspirate, bronchial washing, bronchial alveolar lavage, pleural fluid [aerobe (ASP/TISSUE/SWAB)]) for information on specimen handling requirements.