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Laboratory: Clinical Microbiology
Test Name:
ENDOTRACHEAL SECRETIONS, CULTURE, AEROBIC BACTERIA
Test Code: ETC
Clinical Information:
Test Indications:
To aid in the diagnosis of ventilator-associated pneumonia (VAP).
A tracheal aspirate consists of secretions obtained through a suction catheter used to remove fluid and exudate in the setting of an intubated patient. Current guidelines (1) recommend using a noninvasive method of sample collection such as this to perform semiquantitative cultures to diagnose VAP, rather than invasive respiratory sampling that includes bronchoscopic techniques, e.g., bronchoalveolar lavage. Just as for sputum, endotracheal secretions are contaminated to some degree with oropharyngeal flora.

Laboratory procedure:
Tracheal aspirates are first screened by Gram stain to determine the suitability of the specimen for culture. If no organisms are seen, the sample will not be processed further and a final result will be given as “No organisms seen on microscopic examination; sample not consistent with a bacterial infectious process. Contact the laboratory if further studies are clinically indicated”. The exceptions to this, where samples will be cultured regardless of the Gram stain interpretation, are samples submitted for Legionella, mycobacterial or fungal cultures, as well as samples from cystic fibrosis patients or known immunocompromised patients.

Recommendations:
The specimen type and test requested must be indicated on the requisition.
Endotracheal secretions will be processed for aerobic bacterial culture only. The following specimen types are unsuitable specimens for anaerobic culture and will be rejected: endotracheal secretions, nasotracheal suction, orotracheal suction/aspirate and trans-bronchial biopsy.
If Nocardia, mycobacteria and/or fungi are suspected, this must be requested on the requisition. Please note that increased volume of sample facilitates the isolation of fungi and mycobacteria.
Notify the laboratory in advance and on the requisition if infection with a systemic fungi is suspected (Blastomyces dermatitidis, Coccidioides immitis, Histoplasma capsulatum, Penicillium marneffei, Paracoccidioides brasiliensis).
Tracheal secretions are suitable for Legionella culture. Please refer to Legionella, Respiratory, Culture for recommendations for Legionella testing in patients with pneumonia.
For the laboratory diagnosis of viral or other agents not performed by Shared Health, please refer to the relevant laboratory that performs the testing.
Indicate the suspected diagnosis and current antimicrobial or antifungal therapy on the requisition.
Samples and requisitions must be labeled/completed in accordance with the Shared Health Specimen Acceptance Policy.
Accurate patient identification must be made prior to sample collection. Patient identification should be done in accordance with the site policy.

Patient Preparation Instructions:
Follow protocols outlined by your health care facility for this sample type.
Place aspirate in a trap or sterile screw-cap container.
 
Collection Devices:
Specimens received in other collection devices will not be processed.
Specimen Required: Endotracheal aspirate or secretions, Nasotracheal aspirate or secretions, Tracheostomy aspirate or secretions (Adult and Pediatric)
Referral:
Requisition:
Reference Values:
No growth after 48 hours.
For positive samples, a descriptive report will be provided.
Availability:
Daily
See Also:
More Information:
Specimen Handling:
Local:  ≤2 hrs, store at room temperature. A delay may result in the decreased ability to recover fastidious pathogens and/or overgrowth of upper respiratory flora.
Courier/local storage:  ≤48 hrs (≤24 hrs optimal), store at 4°C.  Ensure samples that are being sent to a referral laboratory are packaged in accordance with Transport of Dangerous Goods recommendations for diagnostic samples.