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AFB Stain (LAB 001015)
Test Mnemonic:


Specimen Requirements:

Collection technique varies by specimen. 


Acceptable specimen containers include Anaerobic transport medium, Eswab™, Falcon tubes, red top tubes with no additive, and sterile containers. 

Minimum Volume:



Room temperature: CSF, Body Fluids, Ocular specimens, Gastric lavages, and tissue/ biopsies.

Refrigerated: Urine, Abscess/Wounds,Feces, Respiratory sources


Stability is dependent on the source and collection container. 

Specimens in non-preserved containers are stable up to 24 hours at appropriate storage. 

Specimens in preservative containers are stable up to 48 hours at appropriate storage. 

Sputum samples will be accepted up to 72 hours from collection at appropriate storage. 

Causes for Rejection:

Urine PCN  volumes <40 mL.

Urine received in preservative tubes.

Cary-Blair transport medium. 

Tissues/Biopsies in formalin. 

Specimens found to be under-labeled, mislabeled, or leaking containers. 

Reference Range:

No acid-fast bacilli observed.

Turnaround Time:

Smears are read and reported within 24 hours of receipt in the lab, when clinically indicated. 

STAT requests will require approval by the Microbiology Director on call. 


Auramine fluorescent stain. 

First time positive Auramine smears are confirmed by Kinyuon stain. 


 Clinical Microbiology


AFB smear; AFB stain; Acid fast Stain

Clinical Indication:

Patients suscpected of Mycobacterial infection. 

CPT 4 Code:



Smear result is include in AFB culture orders. If both are desired, only order AFB culture. 

When ordering tests for which Medicare or Medicaid reimbursement will be sought, physicians should only order tests that are medically necessary for the diagnosis or treatment of the patient. Components of the organ or disease panels may be ordered individually. The diagnostic information must substantiate all tests ordered and must be in the form of an ICD-10 code or its verbal equivalent.
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