Clinics and Departments

Laboratory Services

Lab Dept:

Microbiology/Virology

Test Name:

LEGIONELLA CULTURE

General Information

Lab Order Codes:

LEGC

Synonyms:

Culture, Legionella pneumophila

CPT Codes:

87081 – Culture, presumptive, pathogenic organisms, screening only
87077 – Aerobic isolate, additional methods required for definitive identification of isolates

Test Includes:

Culture for Legionella pneumophila.

Logistics

Lab Testing Sections:

Microbiology

Referred to:

Minnesota Department of Health

Phone Numbers:

MIN Lab: 612-813-5866

STP Lab: 651-220-6555

Test Availability:

Daily, 24 hours

Turnaround Time:

Positive results are usually generated between 2 - 5 days. Negative cultures are final at 14 days.

Special Instructions:

Specimen site and date/time of collection are required for processing.

Specimen

Specimen Type:

Bronchoscopy, lung aspirate, lung biopsy, pleural fluid, or sputum

Container:

Sterile container

Volume:

1 mL fluid

Collection:

Bronchoscopy:

1. Specimen obtained by physician through the biopsy channel of the bronchoscope.
2.
Transfer specimen into a luki tube.
3.
Transport to laboratory within 30 minutes of collection.

Lung Aspirates, Pleural Fluid:

1. Disinfect overlying skin with 2% tincture of iodine.
2.
Obtain specimen via percutaneous needle aspiration or surgery.
3.
Place in sterile container.
4.
Transport to the Microbiology Laboratory immediately at room temperature.

Lung Biopsy:

1. Any visible amount.
2.
Submit in sterile container without formalin.
3.
Lab Staff: Add a few drops of sterile saline to prevent drying.

Sputum (Expectorate):

1. Collect early morning specimen under the direct supervision of a nurse or a physician.
2.
Have patient rinse or gargle with water to remove superficial flora.
3.
Instruct patient to cough deeply to produce a lower respiratory specimen.
4.
Do not submit saliva.

Sputum (Induced):

1. Have patient rinse mouth with water after brushing gums and tongue.
2.
With the aid of a nebulizer, have patients inhale ~25 mL of 3 to 10% sterile saline.
3.
Collect the induced sputum in a sterile container.

Transport/Storage:

Transport to the Microbiology Laboratory immediately at room temperature.

Special Processing:

Refrigerate specimens that cannot be processed within 30 min. If processing is delayed more than 24 hours, freeze specimen at -70C.

Sample Rejection:

Throat and nasopharyngeal specimens are not acceptable due to the presence of normal respiratory flora. Specimen with a transit time exceeding 1 hour after collection; specimen not submitted in appropriate transport container; improperly labeled specimen; insufficient volume; external contamination. If an unacceptable specimen is received, the physician or nursing station will be notified and another specimen will be requested before the specimen is discarded.

Interpretive

Reference Range:

No Legionella pneumophila isolated.

Alert Values:

The physician will be notified of positive results.

Limitations:

Sputum (expectorated), tracheal aspirates, and other specimens having normal respiratory flora are subject to bacterial overgrowth and may mask growth of Legionella. Sensitivity of cultures is relatively low (50% to 80%), however, specificity approaches 100%.

Methodology:

Culture

Additional Information:

The family, Legionellaceae, are ubiquitous, gram-negative, motile, fastidious, aerobic bacilli. Disease outbreaks have been associated with exposure of susceptible individuals to water sources in which legionellae have grown. Legionella sp. cause respiratory illness manifested primarily by pneumonia or Pontiac fever, a non-pneumonic, influenza-like illness. During an American Legion Convention in Philadelphia in 1976, an epidemic of pneumonia caused 34 deaths. Sputum characterized by acute inflammatory features, without a classical pattern of bacteria, may represent Legionella, influenza, or respiratory syncytial virus.

References:

Cook, JH, and M Pezzlo (1992). Specimen receipt and accessioning. Section 1. Aerobic bacteriology, 1.2.1-4. In HD Isenberg (ed) Clinical Microbiology Procedures Handbook. American Society for Microbiology, Washington DC

Miller, J Michael (1999) A Guide To Specimen Management in Clinical Microbiology, American Society for Microbiology, Washington DC

Miller, J Michael, and HT Holmes (1999) Specimen Collection, Transport, and Storage In PR Murray et al, (ed), Manual of Clinical Microbiology, 7th edition, American Society for Microbiology, Washington DC, pp 33-104

Test Updates:

6/2/2014: DFA no longer performed as part of this test.



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