Diagnosis and management of severe pulmonary and extrapulmonary tuberculosis in critically ill patients: A mini review for clinicians

Table 2 Methods of collection and processing sputum samples for diagnosis of tuberculosis[42]

Specimen	Amount	Preservation	Comment
Sputum	2-5 mL	Unprocessed	At least 2x, recommended to be in the morning on an empty stomach
Induced sputum	2-5 mL	Unprocessed	Expectoration following inhalation of 3% NaCl solution
Bronchial secretions or bronchoalveolar lavage samples	2-5 mL	Unprocessed	BAL-ELISPOT should be performed on the same day of sample collection
Gastric aspirates	> 2 mL	In 1-2 mL phosphate buffer (trinatrium phosphate)	Early morning gastric aspirates, only when sputum cannot be aspirated and when bronchoscopy and lavage is not indicated

BAL-ELISPOT: Bronchoalveolar lavage enzyme-linked immunosorbent spot assay used in detection of tuberculosis.