AFB Culture

Method Name

Reference Laboratory


AFB Culture; AFB Smear & Culture, Micro Culture Request AFB

Specimen Required

sputum, bronchial washings, fluid aspirates, CSF, tissue, first a.m. urine or stool in a clean, sterile, leakproof container

Specimen Minimum Volume

1 mL for CSF, 5 mL for all others

Specimen Stability Information

Transport at room temperature, must be received within 24 hours of collection *NOTE* Specimens that do not meet the above criteria will be rejected.

Special Instructions

Specimens must be labeled with complete source and body site information. Exam includes both smear and culture. AFB cultures are held for 8 weeks of incubation. See attached chart for specific specimen collection guidelines: n -> Abscess contents, aspirated fluid – As much as possible should be aspirated into a syringe with needle removed. Cap or transfer to a sterile leakproof container or Port a Cul vial prior to transport of the specimen. If there is little material in the syringe, a small amount of sterile 0.85% NaCl or sterile broth should be drawn through the syringe and then transfer the specimen to a sterile tube. n -> Body fluids (pleural, pericardial, peritoneal, etc.) – Collect as much as possible in a sterile, leakproof container, Port a Cul vial, or syringe with needle removed and capped. n -> Bone – Place bone in a sterile, leakproof container without fixative or preservative. n -> Broncho-alveolar, lavage or bronchial washings – collect greater than 5 mL in a sterile, leakproof container. Avoid contaminating bronchoscope with tap water. Saprophytic mycobacteria may produce false-positive culture or smear results. n -> CSF – Specimens must be collected prior to the start of antimicrobial therapy. The skin must be disinfected with an antiseptic solution in the area to be sampled. If tests other than culture are requested, the microbiology sample should be collected after the first few milliliters are drawn (tube 2 or higher). The specimen must be transported immediately to the laboratory. Specimens should never be refrigerated. Specimen is also acceptable for fungal and viral cultures if sufficient volume is obtained (1 mL for each test ordered). n -> Lymph node – Place node or portion of node in a sterile, leakproof container without fixative or preservative. Add sufficient physiological saline to keep moist in transit (if not transported within 1 hr) Collect aseptically, and avoid indigenous flora. Select a caseous portion if available. n -> Skin lesion material – Submit biopsy specimen in a sterile, leakproof container without fixative or preservative. Submit aspirates in a syringe with the needle removed and capped or transfer specimen to a sterile container. If specimen is not transported within an hour, add physiologic saline to keep moist in transit. Swabs in transport medium (Amies or Stuarts) are not acceptable. For cutaneous ulcer, collect biopsy sample from periphery of lesions, or aspirate material from under margin of lesion. If infection was acquired in Africa, Australia, Mexico, South America, Indonesia, New Guinea, or Malaysia, note on request, because Mycobacterium ulcerans may require prolonged incubation for primary isolation. n -> Sputum – Collect 5-10 mL in sterile, wax-free, leakproof container. Collect an early-morning specimen from a deep, productive cough on at least 3 consecutive days. Do not pool specimens. For follow-up of patients on therapy, collect at weekly intervals, beginning 3 weeks after initiation of therapy. Indicate on request if specimen is induced sputum. For expectorated sputum, instruct patient on how to produce sputum specimen as distinct from saliva or nasopharyngeal discharge. Have the patient rinse mouth with water before collecting sputum to minimize contaminating specimen with food particles, mouthwash, or oral drugs – which may inhibit the growth of mycobacteria. For induced sputum, use sterile hypertonic saline. Avoid sputum contamination with nebulizer reservoir water. Saprophytic mycobacteria in tap water may produce false-positive culture or smear results. n -> Stool – Collect in a clean, dry leak-proof sterile container. Specimen will be processed for culture only. Direct smears are not performed on stool specimens. n -> Tissue Biopsy Sample – Collect 1 gram of tissue, if possible, in sterile, leakproof container without fixativ

Performing Laboratory

As ordered. Turn around time is 8 weeks.