Sign in →

Test Code CXAFB Culture, Acid Fast Bacilli

Performing Laboratory

Hunterdon Medical Center Laboratory

Special Instructions

The reliability of cultures for Mycobacteria depends on the quality of the specimen. Many specimens contain contaminating micro-organisms; therefore the specimen must be as fresh as possible or refrigerated, if processing is delayed to avoid overgrowth of other organisms.

Specimen Required

All specimens are to be collected in clean, sterile, leak-proof containers.

Specimen Type

  • Sputum:
  • Three first morning specimens of 5-10ml collected on consecutive days.
  • Nebulized (induced sputum)- label as nebulized or induced.
  • Bronchoscopy washings or brushes, aspiration of bronchial secretions.
  • Transtracheal aspirates
  • Urine: First morning specimen submitted on 3 successive days. 10ml minimum needed.
  • Cerebrospinal fluid (CSF): 2ml
  • Body Fluids: 2ml
    • Pleural, peritoneal, pericardial, synovial.
  • Tissues:  Incisions or excision biopsy, skin lesions.
  • Drainage - wounds
  • Fluid or aspirate only. No swabs
  •  Feces: Use HMC order code: CAFBR 
  • Para-Pak® Clean Vial (white cap). Test performed at Mayo Medical Laboratories (MML)
  • Link to MML:
  • See related tests. (Click for link to CAFBR)
  •  Blood: Use HMC order code: CAFBB
  • Green top tube: 10ml for each culture. Test performed at Mayo Medical Laboratories (MML).
  • Link to MML:
  • See related tests. (Click for link to CAFBB)
  •  Bone Marrow: Use HMC order code: CAFBR
  • Green top tube: 10ml for each culture. Test performed at Mayo Medical Laboratories (MML).
  • Link to MML:
  • See related tests. (Click to link for CAFBR)

Specimen Transport Temperature

Ambient: Deliver within 2 hours.

If delivery is delayed: Refrigerate 2- 8°C* 

*Note: See Specimen Stability (below)

Reference Values

No AFB Isolated after 8 weeks.

 

Cultures are read three times per week for 8 weeks.

Specimen Stability Information

Specimen Type Temperature Time Frame
Sputum/Urine Series of Three Specimens Refrigerated 2-8°C 72 hours
All other specimens Refrigerated 2-8°C 24 hours

Reject Due To

1. Insufficient quantity of specimen:

Sputum: less than 1-2 ml

Urine: less than 5 ml.

2. Swabs: specimen does not provide enough material for culture.,

3. 24 hour specimens.

4. Spilled specimens.

5. Multiple specimens from the same site collected on the same day.

6. CSF: AFB and fungal cultures will only be performed if the cell count is abnormal and either protein or

    glucose levels are abnormal.

    Specimens that do not meet these criteria will be canceled and the test(s) designated as "Not Indicated".

    A report will be generated and the CSF will be held for a minimum of 7 days.

Day(s) Performed

Monday through Sunday

Method Name

Conventional culture method with acid fast bacilli stain by fluorescent or Kinyoun method. Specimens with positive stains will be referred to Mayo Medical Laboratories (MML) for Mycobacterium tuberculosis by PCR. See related test. Click on link for test information.

 

Suspicious growth is stained for acid fast bacilli. Positive colonies are referred to Mayo Medical Laboratories (MML) for identification and susceptibility testing will be performed by MML, if appropriate.