Test Code LAB266 Acid-Fast Bacilli (AFB) Stain
Methodology
Fluorochrome Stain Technique
Testing Algorithm:
- If acid-fast stain is requested, then Mycobacteriology (AFB) Culture (LAB877) will be performed, at an additional charge.
- If acid-fast stain on a respiratory related specimen (i.e., bronchial alveolar lavage, bronchial washing, induced sputum, sputum, tracheal aspirate or pleural fluid) is positive, then PCR for Mycobacterium tuberculosis complex (MTBC) will be performed, at an additional charge.
Note: Acid-fast stain is not routinely performed on cerebrospinal fluid (CSF). Call Barnes-Jewish Hospital Microbiology Laboratory at 314-362-3898 if stain is medically indicated.
Performing Laboratory
Barnes-Jewish Hospital Laboratory
Specimen Requirements
Acceptable Specimens:
Note: Only 1 ESwab is required when this test and Mycobacteriology culture (LAB877, LAB7000, LAB7001)
Abscess, aspirate, or wound: ≥1 mL in a leakproof screw-capped, sterile container or 1 ESwab per test request in sterile collection tube
Biopsy or tissue: ≥1 g in a leakproof screw-capped, sterile container
Bronchial or tracheal: ≥5 mL in a leakproof screw-capped, sterile container
Eye: conjunctiva and cornea-1 ESwab Minitip Collection Kit; ocular fluid (anterior chamber, aqueous humor, vitreous)-≥0.5 mL in a leakproof screw-capped, sterile container
Sterile Fluids (pericardial, pleural, synovial, etc.): ≥1 mL in a leakproof screw-capped, sterile container
Gastric aspirate: ≥5 mL in a leakproof screw-capped, sterile container
Sputum: ≥5 mL in a leakproof screw-capped, sterile container
Unacceptable Specimens:
Urine, stool
Specimen collected with ESwab Collection Kit is unacceptable if received without fluid or swab in the transport tube.
Collection Procedure:
Note: Specimen source is required.
Abscess, Aspirate, or Wound
1. Disinfect surface of abscess or wound.
2. Aseptically collect purulent material by aspiration (≥ 1 mL) or by using an ESwab. Frequently, viable organisms are only associated with abscess wall, so adequately sample this area. If material is aspirated, aseptically inject specimen into a leakproof screw-capped, sterile container or a plain, red-top tube.
3. If ESwab is used, return ESwab into transport tube following instructions on kit.
4. Maintain sterility and transport promptly to laboratory.
5. If transport is delayed, keep specimen at room temperature.
Biopsy or Tissue
1. Aseptically collect ≥1 g of tissue from border of lesion. Because there may be only a few viable organisms in a lesion, specimen must be large enough to permit their recovery.
2. Place specimen in a leakproof screw-capped, sterile container.
3. Maintain sterility and transport promptly to laboratory.
4. If transport is delayed, keep specimen at room temperature.
Bronchial or Tracheal
1. Aseptically collect ≥5 mL.
2. Place specimen in a leakproof screw-capped, sterile container.
3. Maintain sterility and tranport promptly to laboratory.
4. If transport is delayed, refrigerate specimen.
Eye - Conjunctiva or cornea
1. Call Barnes-Jewish Hospital Laboratory Customer Service at 314-362-1470 to obtain ESwab Minitip Collection Kit.
2. Collect specimen before application of topical anesthetics because topical anesthetics possess antimicrobial activity.
3. Cleanse skin around eye with mild antiseptic.
4. Gently remove makeup and ointment with sterile cotton and saline.
5. Collect specimen by passing ESwab 2 times over lower conjunctiva or over cornea. Avoid eyelid border and lashes (culture these separately in a similar fashion, if indicated).
6. Place ESwab in transport tube following instructions on kit.
7. Maintain sterility and transport promptly to laboratory.
8. If transport is delayed, keep specimen at room temperature.
Eye - Ocular fluid (anterior chamber, aqueous humor, vitreous)
1. Aseptically collect ≥0.5 mL of fluid.
2. Place specimen in a leakproof screw-capped, sterile container.
3. Maintain sterility and transport promptly to laboratory.
4. If transport is delayed, keep specime at room temperature.
Sterile Fluid (Pericardial, Pleural, Synovial, etc.)
1. Aseptically collect ≥1 mL of fluid.
2. Place specimen in a leakproof screw-capped, sterile container.
3. Maintain sterility and transport promptly to laboratory.4. If transport is delayed, keep specimen at room temperature.
Gastric Aspirate
1. Aseptically collect ≥5 mL early-morning specimen in a leakproof screw-capped, sterile container.Specimen received in the lab >4 hours between specimen collection and the time the specimen is processed in the lab will be canceled. Specimen received after 900AM will be canceled. It is optimal to collect a specimen each day for 3 consecutive days.
2. Maintain sterility and transport promptly to laboratory.
Sputum
1. Aseptically collect early-morning specimen in a leakproof screw-capped, sterile container. It is optimal to collect a specimen each day for 3 consecutive days. (Saliva is not acceptable.)
2. Instruct patient to brush his/her teeth and rinse mouth well with water.
3. Have patient remove dentures.
4. Instruct patient to take a deep breath, hold it momentarily, and then cough deeply and vigorously into container. Collect ≥5 mL of discharged material.
5. Maintain sterility and transport promptly to laboratory.
6. If transport is delayed, refrigerate specimen.
Specimen Transport Temperature
Ambient/Refrigerate OK
Reference Values
No acid-fast bacilli seen.
Literature Reference:
Della-Latta P. Mycobacteriology and antimycobacterial susceptibility testing. In: Leber, Amy, ed. Clinical microbiology procedures handbook. 4th ed. Washington DC: American Society for Microbiology;2016;7.1-7.6.
Day(s) Test Set Up
Monday through Sunday
Cut-off time: 0900
Turnaround Time:
STAT: not available
Routine: results available the day of testing
Test Classification and CPT Coding
87116-Culture, Mycobacterium
87206-Smear fluorescent, acid-fast
Additional Information
For BJH Laboratory Use Only
Minimum Volume:
Abscess or wound: 0.5 mL in a leakproof screw-capped, sterile container or 1 ESwab per test request in sterile collection tube
Aspirate: 0.5 mL in a leakproof screw-capped, sterile container
Biopsy or tissue: any amount in a leakproof screw-capped, sterile container
Eye: conjunctiva or cornea-1 ESwab Minitip Collection Kit; ocular fluid (anterior chamber, aqueous humor, vitreous) - 0.5 mL in a leakproof screw-capped, sterile container
Sterile Fluids (CSF, pericardial, pleural, synovial, etc.): 0.5 mL in a leakproof screw-capped, sterile container
Gastric Aspirate: 0.5 mL in a leakproof screw-capped, sterile container
Respiratory: 0.5 mL in a leakproof screw-capped, sterile container
Laboratory Processing Instructions:
Test performed in BJH Microbiology.