Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1418 page)

   Patients with LRT infections typically present with a constellation of symptoms of varying severity, including fever, cough, sputum production, difficulty breathing, and shortness of breath. Common bacterial pathogens are less commonly associated with coryza and rhinorrhea than are respiratory viruses and mycoplasmas. Symptoms and clinical examination may help distinguish tracheobronchitis, bronchiolitis, and pneumonia from one another.

   Special Collection and Transport Instructions

   For expectorated sputum samples, patient instruction is critical for collection of a good-quality, informative sample.

   Specimens must be collected in sterile transport containers with tight-fitting lids.

   First-morning specimens are usually most sensitive because of pooling of secretions during sleep.

   Contamination is reduced for patients who brush their teeth and gargle with water or saline just before specimen collection.

   The patient must understand that sputum from a deep cough is needed, and saliva should not be spit into the collection cup.

   Sputum production may be improved by chest wall percussive techniques.

   Specimens obtained by more invasive procedures, such as sputum induction, BAL, tracheal aspirate, and lung puncture, are collected by physicians or respiratory therapists trained with specific collection protocols.

   Specimens must be transported to the laboratory as quickly as possible at room temperature.

   Use

   These cultures are used to identify bacterial pathogens responsible for LRT infections by culture of sputum. A variety of human pathogens may cause lower respiratory infections; there is a large overlap in the clinical signs and symptoms.

   Method: