Laboratory Services

Mycobacteria and Nocardia Culture, Varies

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Updated Test Information:

Test Description
Mycobacteria and Nocardia Culture, Varies
Synonym(s)

Acid Fast Bacilli (AFB) Smear; Acid Fast Smear; Bacillus; acid-fast; Culture for TB (Tuberculosis); Mycobacteria; Nocardia; Smear; Acid Fast Bacilli-AFB; 5180-CTB; TB (Tuberculosis) Culture

Test ID
CTB
General Information

Useful For:



  • Detection and identification of Mycobacterium species, Nocardia species, and other aerobic actinomycetes

  • Determination / differentiation of etiology associated with suspected acute meningitis or encephalitis in immunocompromised patients or those receiving antiobiotic therapy

  • Identification is performed using the Hologic/GenProbe AccuProbes for selected Mycobacterium species, matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry, or 500-base pair 16S rRNA gene sequencing

  • M tuberculosis complex species identification can be done upon request using rapid PCR targeting the regions of difference (RD) genomic areas

Specimen Type

  • Body fluid

  • Bone marrow

  • Gastric washing

  • Respiratory - BAL, bronchial washing, sputum

  • Stool

  • Random Urine

  • Swab - wound, tissue, or body fluid

Specimen Requirements

  • Body fluid:

    • Container/Tube: Sterile container

    • Specimen Volume: 1 mL



  • Bone marrow:

    • Container/Tube: SPS/Isolator System or green top (lithium heparin)

    • Specimen Volume: Entire collection



  • Gastric washing:

    • Container/Tube: Sterile container

    • Specimen Volume: 10 mL

    • Collection Instructions: Neutralize specimen within 4 hours of collection with 100 mg of sodium carbonate per 5 to 10 mL of gastric wash.



  • Respiratory - BAL, bronchial washing, sputum:

    • Container/Tube: Sterile container

    • Specimen Volume: 3 mL

    • Collect 3 respiratory specimens for acid-fast smears and culture in patients with clinical and chest X-ray findings compatible with tuberculosis

    • These 3 specimens should be collected at 8- to 24-hour intervals (24 hours when possible) and should include at least 1 first-morning specimen.



  • Stool:

    • Container/Tube: Sterile container

    • Specimen Volume: 5-10 g



  • Random Urine:

    • Container/Tube: Sterile container

    • Specimen Volume: 20-50 mL



  • Swab - wound, tissue, or body fluid:

    • Fresh tissue or body fluid is the preferred specimen type instead of a swab specimen

    • Container/Tube: Culture transport swab (noncharcoal) culturette

    • Before collecting specimen, wipe away any excessive amount of secretion and discharge, if appropriate

    • Obtain secretions or fluid from source with sterile swab

    • If smear and culture are requested or both a bacterial culture and mycobacterial culture are requested, collect a second swab to maximize test sensitivity.



  • Tissue:

    • Container/Tube: Sterile container

    • Specimen Volume: 5-10 mm



Required Information

  • Specimen source is required

  • Alert the laboratory if Mycobacterium genavense is suspected, as this species requires addition of mycobactin J to the culture medium for optimal growth and recovery.

Stability

  • Refrigerated (preferred): 7 days

  • Ambient: 7 days

Unacceptable Specimen Conditions

  • Blood or fixed tissue

  • specimen in viral transport medium (including but not limited to M4, M5, BD viral transport media, thioglycolate broth)

  • swab sources of respiratory fluids, nasal, sinus, ear, mouth, throat, or scalp

  • wood shaft or charcoal swab

  • petri dish

Limitations

  • Recovery of mycobacteria is dependent on the number of organisms present in the specimen, specimen collection methods, methods of processing, and patient factors such as the use of antimycobacteria therapy

  • The use of BBL MGIT PANTA antibiotic mixture, although necessary for all nonsterile specimens, may have inhibitory effects on some mycobacteria.

Methodology

Automated Detection of Positive Cultures Followed by Organism Identification with Rapid Methods, which may include Nucleic Acid Probes, DNA Sequencing, and Matrix Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) Mass Spectrometry

Estimated TAT

42-70 days

Testing Schedule

Monday through Sunday

Retention

Raw specimen 3-7 days; Isolates from positive cultures kept 1 year

CPT Code(s)

  • 87116-Mycobacterial Culture

  • 87015-Mycobacteria Culture, Concentration (if appropriate)

  • 87118-Id MALDI-TOF Mass Spec AFB (if appropriate)

  • 87150-Mycobacteria Probe Ident, Solid (if appropriate)

  • 87150-Mycobacteria Probe Ident, Broth(if appropriate)

  • 87150-Id, Mtb Speciation, PCR (if appropriate)

  • 87153-Mycobacteria Identification by Sequencing (if appropriate)

  • 87176-Tissue Processing (if appropriate)

Additional Information
Minimum Sample Volume

Body Fluid: 1.5 mL
Respiratory Specimen: 3 mL
Fresh Tissue: pea-sized piece

Reference Range

Negative (at 42 days)

Reflex Conditions

  • ISMY: ID by 16S Sequencing

  • RMALM: Id MALDI-TOF Mass Spec AFB

  • RTBSP: Id, Mtb Speciation, PCR

  • TBMP: Mycobacteria Probe Ident

  • TBPB: Mycobacteria Probe Ident Broth

  • TBT: Concentration, Mycobacteria

  • TISSR: Tissue Processing

  • LCTB: Id, MTB complex Rapid PCR

Performing Lab

Mayo

LOINC Code(s)

50941-4