Laboratory Test Information Guide

Details for Mycobacterium Culture

Test Name: Mycobacterium Culture
Alternate Name(s): Acid fast Bacilli Culture (AFB)
Tuberculosis Culture
TB Culture
Laboratory: Microbiology (VH)
Specimen Type: -Blood
-Body Fluids (pleural, pericardial, peritoneal, etc.)
-Bone Marrow
-Gastric Lavage
-Respiratory (includes bronchial alveolar lavages, sputum or tracheal aspirations)
Collection Information: Collect samples aseptically. Swabs are not accepted. Do not use fixatives or preservatives. Do not use waxed containers.

Blood - Collect sample aseptically into a 6 mL Dark Green (Sodium Heparin) top Vacutainer tube. DO NOT SPIN

Body Fluids - Collect as much as possible (10-15 mL minimum) in a sterile container. Samples that may contain fibrinogen should be collected in a 6 mL Green top (heparinized) Vacutainer tube to prevent clotting.

Bone - Submit in a sterile container.

Bone Marrow - Collect aseptically into 6 mL Green top Vacutainer tube.

CSF - Where possible collect a minimum of 2mL in a sterile container. Specimens <0.5 mL will be rejected

Gastric Lavage - Obtain Gastric Lavage Transport media from the Microbiology Laboratory. Collect fasting, early morning sample to recover sputum swallowed during sleep. Following collection, the sample must be neutralized immediately by transferring it to the transport container which contains sodium carbonate.

Bronchial Alveolar Lavages - Submit a minimum of 5 mL in a sterile container. Submit a post-bronchoscopy sputum as well.

Sputum - Where feasible, three sputum specimens (either spontaneous or induced) can be collected on the same day, a minimum of one hour apart, with at least one of them taken in the early morning.
(Same-day samples should be collected with an interval of as little as 1 hour between each collection may be especially helpful to reduce patient drop-out and make faster decisions about TB infection control and discharge from respiratory isolation).
Do not have the patient rinse mouth with tap water before producing specimen. Instruct the patient not to expectorate saliva or postnasal discharge. Do not pool samples. Select blood-stained or purulent portion and send 5-10 mL in sterile container.

Tracheal Aspiration - Collect as much as posssible in a sterile container.

Tissue - Select caseous portion if available. Submit as much as possible in a sterile container. Do not immerse in saline or other fluid.

Urine - Send the total volume of first morning specimen obtained by midstream collection or catheterization in sterile container.
(Do not send in a Vacutainer with preservative)

Wound Material - Send as much as possible of biopsy material or aspirate in a sterile container.
Test Schedule: Referred out weekdays to Public Health Laboratory.

Microscopic results are reported as soon as possible. Culture requires 8 weeks.

Positives are reported upon detection.
Turnaround time from when specimen
is received in testing laboratory:
65 days
Reference Range:  
Effective Date: 2010-06-10
Revised Date: 2019-01-14
Critical Value:  
Interpretive Comments: AMTD: Specimens positive for AFB by smear may be tested by the Amplified Mycobacterium tuberculosis Direct test which detects M. tuberculosis complex directly in clinical specimens. This test is restricted to specimens from new untreated cases. Only sputum, BAL and tracheal aspirates will be tested.

AMTD may be performed on smear negative specimens when TB is clinically suspected. In these cases make a special request to the lab, prior to specimen submission.
Special Processing:  
Method of Analysis: Microscopy, culture, PCR
Critical Information Required:  
Storage & Shipment: Respiratory specimens must be refrigerated. Other specimens must be left at room temperature. The specimen must be received within 24 hours of collection.
System Codes: 
Referred To: Public Health Laboratory

Questions? Comments? Contact Laura Gopaul