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Test Code C AFB Misc AFB Culture

Biohazard Infectious

Clinical System Name

AFB Culture


AFB Stain

AFB Smear

Acid Fast Stain

Acid Fast Bacteria

Auramine Stain

Modified Kinyoun

Mycobacteria Culture


Mycobacterium tuberculosis


Includes Culture and Stain for Acid Fast Bacteria (Mycobacteria). Ordering a separate AFB Stain is not necessary. 


Gastric aspirates are an acceptable alternative to sputum for babies and young children who cannot produce a sputum sample. See below for collection requirements.  


If patient history is highly suspicious of Mycobacterium tuberculosis please communicate this information to the laboratory.

Sample Requirements


  • Tissue or Body Fluid: Piece of tissue, preferably 0.5 cm3, , or 1-3 ml of body fluid. Swabs are unacceptable for AFB culture.
  • CSF: Minimum of 3 ml of fluid. Note: AFB culture of CSF requires Infectious Disease approval.
  • Expectorated or Induced Sputum: Minimum 3 ml specimen, optimal 5-10 ml. Three consecutive sputum samples should be collected at a minimum of 8 hour intervals.
  • CF Patient's Sputum: minimum of 0.5g (not necessary to collect 3 samples in this patient population)
  • Gastric Aspirates: Prior to collecting sample, obtain 50 ml transport tube containing 100mg of Sodium Carbonate from Microbiology Lab (7-2585). Collect fasting gastric aspirate specimen (minimum of 5.0 ml) on 3 consecutive days (24 hours apart).
  • Blood or Bone Marrow: See Blood Culture, AFB and Bone Marrow Culture for sample requirements.
  • Urine: Minimum of 40 ml, first morning urine.
  • Stool: Only available with ID consultat/approval. Submit 1 gram of stool.


Container: Sterile Container

Preferred Vol: See above

Minimum Vol: See above


Swabs are unacceptable and will be rejected due to low yield. 

Processing Instructions


CPA: Send sample to Microbiology for processing.  If the sample is shared and only one tube, syringe or other container is received, affix shared sample label and send entire sample plus requisition to Microbiology.


Off-site collection: Off-site Children's Lab locations should send the sample to SCH Microbiology Laboratory for processing. If the sample has an additional bacterial culture request, refer to the specific protocol and set up culture in biological safety hood if appropriate. Sample should be kept refrigerated prior to and during courier transport to SCH Microbiology Laboratory for AFB set up. 


Other off-site locations, refrigerate sample prior to and during courier transport to SCH Microbiology Laboratory.


Temp Time
Room temp 30 minutes
Refrigerated 24 hours
Frozen N



Procedure Performed Turn Around Time (TAT)
Stain 24/7 24 hours
Culture 24/7 8 weeks


Performing Laboratory

Seattle Children's Laboratory



Microbiology Laboratory

CPT Codes



This test is not limited to the CPT codes listed.  Others may be added as more testing is necessary and depending on the pathogens isolated (example: MIC's and ID codes)

Notifiable Result

Mycobacterium tuberculosis is a notifiable condition under Washington State Law


See Link below for Notifiable Conditions for WA State:


See Link below for PDF of phone numbers for Local Health jurisdictions (by County) in WA State:

Reporting Information

Negative Preliminary Report: 24 - 48 hours

Negative Final Report: 8 weeks


The report will be updated and the provider will be notified if growth is detected within the 8 week incubation period.