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HelpTest Code AFBC Culture-TB (AFB)
Clinical Indications
Diagnosis of mycobacterial infections
AFB smear will automatically be performed
on all respiratory specimens.
Additional Test Codes
Epic Order Code: Culture-TB (AFB) (aka
TB Culture)
Sunquest Order Code: AFBC
Px Order Code: LAB4027
Specimen Collection Type
Varies
Fluids, tissues, bones, respiratory specimens (bronchial alveolar
lavage, bronchial washing, sputum and tracheal aspirate), gastric,
stool, and urine specimens submit in sterile container
Fresh tissue or fluid is preferred over swabs.
Gastric aspirate collections must be coordinated with Laboratory as
these specimens must be processed within 4 hours of collection.
To rule out M. tuberculosis respiratory infection, collect 3
samples at least 8 hours apart. At least one sample should be a
first morning collection.
Minimum Collection Volume
Body fluid: 1 mL
Respiratory specimen: 2-5 mL
Tissue: pea-sized piece
Urine: 20+ mL; first morning collection preferred
Stool: pea-sized portion or 0.5 mL
Gastric aspirate: 10 mL
Reference Range
No growth
Critical Value
Growth of Mycobacterium tuberculosis
Acid fast bacilli detected on respiratory specimens smear from
non-cystic fibrosis patients.
Interpretation
A positive smear result indicates the presence of acid fast
bacilli.
A negative smear result cannot exclude the possibility of
mycobacterial infection. Correlation with culture results is
required.
Positive cultures are reported when growth is detected.
Organism identification may require isolate be sent to reference
laboratory.
Susceptibility testing is performed at a reference laboratory upon
request.
Negative cultures are incubated for 6 weeks before a final negative
report.
Rejection Criteria
Specimens in formalin or other preservatives or fixatives.
Gastric lavage not received within 4 hours.
24 hour pooled sputum or urine.
Specimen Availability for Add-on Testing
Swabs: N/A
Fluids/Tissues: 5 days
Respiratory: 3 days
Flocked swabs (ESwabs): 5 days
Urine: 48 hours
Stool: 4 hours
Gastric aspirate: N/A
Specimen Stability
3 days at 2-8°C
Day(s) Performed
Specimens are processed Monday through Friday and must be received by the laboratory by 11am. Any specimens received after this time will be processed the next weekday. Specimens received over the weekend will be processed on Monday.
Performing Lab- Department
TUKHS-BH-Microbiology
CPT Code
87116
LOINC Code
543-9
Test Alias
TUBERCULOSIS CULTURE
ACID FAST
CULTURE
Additional Information / Notes
N/A