Test:

AFB Culture w/ Smear

Supplemental Forms Required - Mycobacterium tuberculosis (MTB) Supplemental

 
  Synonym:

AFB Culture, TB Culture w/ smear

 
  Method:

Standard reference procedures for stain and culture. Molecular sequencing used for most identification. DNA probes available for M. tuberculosis complex, M. avium-intracellulare complex, M. gordonae as indicated.

 
  Availability:

Monday - Friday by 0800. Stat requests are performed by approval of a pathologist.

 
  Specimen:

Sputum: early morning collection in a sterile leak-proof container. Limit the number of samples to 3 specimens collected consecutively in 8- to 24-hour intervals, with at least one being an early morning specimen. Early morning sputum specimen is preferred. Approval is required for additional specimens. The number of specimens that should be submitted is related to the results of early smear examinations

 
  Collection Device:

Early morning urine in a sterile leak-proof container. Gastric aspirate, body fluid and tissue in a sterile leak-proof container. Store and transport refrigerated at 2-8°C.

Specimen Labeling: Test subject to CLIA regulations and required 2 patient identifiers on specimen container and requisition forms.

 
  Volume:

5-20 ml sputum, at least 1-2 ml CSF, 5-20 ml gastric aspirate, >= 40ml urine, 5-50 ml body fluid, or 1 gram of tissue.

 
  Storage/Transport:

Prior to and during shipment: Refrigerate 2-8°C

Shipping instructions, including specimen-handling requirements during transport:

Package and ship as UN3373 Category B, Biological Substance. Place in biohazard bag with absorbent material. Refrigerated specimen should be shipped on cold packs. Transport by NPHL ground courier (NPHL brown shipper not required). If courier not available, contact Client Services (866) 290-1406 to arrange pickup. See instructions and shipping address: http://nphl.org/

 
  Unacceptable:

Multiple same-site specimens in 24 hour period, dry material, non-sterile or leaking containers, insufficient volume (<2 mL sputum or <1 mL body fuid), stools, and swabs

 
  Specimen Stability:

Refrigerate 2-8°C

 
  Reference Interval:

Preliminary: Acid fast stain at 24 hours, Negative at 4 weeks

Final: Negative at 8 weeks

Positive cultures are reported as soon as detected.

Note: Identification performed on positives.

Susceptibility performed on Mycobacterium spp other than M. tuberculosis complex isolates by request.

Susceptibility testing of M. gordonae from sputum is usually inappropriate. Standard reference procedures for stain and culture. Biochemical standard reference procedures are used for rapid growers. DNA probes available for M. tuberculosis complex, M. avium-intracellulare complex, M. gordonae as indicated.

 
  Reportable Disease:

MTB complex will be reported immediately to local or state health department. Refer to Nebraska DHHS Title 173, Communicable Diseases

 
  Comments:

Collection of early morning specimens of urine and sputum on each of 3 consecutive days is optimum. Gastric lavage specimens must be neutralized with sodium bicarbonate if transport delayed > 4 hours. Collect gastric aspirate 8 hours after food ingestion. Suggest collection of gastric aspirates for 3 consecutive days. Indicate source of specimen on the lab form. Tissue: submit skin lesions or other tissue; keep moistened with sterile saline. Indicate if Mycobacteria other than tuberculosis (MOTT) are suspected. This may expedite identification. Client is notified of positive stain/culture. Additional information to include when submitting a specimen for culture; patient's PPD status; BCG immunization history; prior anti-tuberculous therapy.

Contact AFB lab at 402-552-3087 for questions.

 
  Revised: 9/2/2020