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Test Code C AFB Acid-Fast Bacillus (AFB) Culture

Important Note

Reflex testing ordered as appropiate

Performing Laboratory

Memorial Hospital-Microbiology Laboratory 304-388-9353

Test Profile

Acid-Fast work-up and direct acid-fast smear.

DO NOT ORDER AN ADDITIONAL ACID-FAST (TB) SMEAR.

Specimen Requirements

For diagnostic purposes, clinical specimens should be collected before the initiation of therapy since even a few days of treatment may render the culture negative.

Submit only 1 of the following specimens:

Specimen Type Container/Tube Specimen Volume Collection Instructions
Body Fluid Sterile Container 1 mL  
Bone Marrow Lithium Heparin (Green top) Entire Collection  
Gastric Washing Sterile Container 10 mL Neutralize specimen within 4 hrs of collection with 100mg sodium carbonate per 5-10 mL of gastric wash
Respiratory (Bronchoalveolar lavage, broncial washing, sputum) Sterile Container 3 mL Collect 3 respiratory specimens for acid-fast smears and culture in patients with clinical and chest x-ray findings compatible with TB. These specimens should be collected at 8-24 hour intervals (24 hr when possible) and should include at least 1 first-morning specimen.
Stool Stool Collection Kit, Random 5-10 g  
Tissue Sterile Container 5-10 mm Collect a fresh tissue specimen
Urine Sterile Container 20-50 mL Collect a random urine specimen

Specimen Rejection

  • Improperly labeled, collected, stored, and transported
Tissue, Bone, Fluid Abscesses Frozen specimens, specimen in formalin or alcohol.  
Sputum/Bronchial  Swabs, specimen in formalin or alcohol
CSF Fluid <0.5 mL, swabs
Urine <50 mL, pooled specimens, more than 1 specimen/day
Stool Frozen

Storage and Stability

Specimen should be examined as soon as possible.  Store at 4o C if delayed.

Reference Values

Negative for AFB

Critical Result- All Positives

Methodology

Smears are performed routinely on all specimens except urines. Susceptibilities are automatically performed on tuberculosis (TB) complex-positive cultures by West Virginia State Hygienic Lab. Susceptibility testing for non-TB complex is by special request only and will be performed at an additional charge.

Days Test Set Up and Turnaround

Monday through Sunday, Continuously

Turn around time depends on growth

CPT Coding

87116

87206