Performed
Typically all days.
Methodology
The specimen is screened for M. tuberculosis complex with a nucleic acid amplification test (TB NAAT). A smear for AFB is performed and the specimen is cultured on solid and liquid media (see AFB7 for more details). Mycobacteria or partially acid fast organisms are identified to the full extent possible, such as to the species or subspecies level (AFB4).
Turnaround Time
- TB NAAT is reported within 1-3 days.
- AFB Smear reported within 24 hours. Note that AFB smears are not performed for urine, stool, or blood.
- The final report for the AFB culture is issued at 6 weeks. Solid media cultures are read at 1, 3, and 6 weeks. Liquid media cultures are continuously monitored. Positive cultures are reported at the time of positivity and negative cultures are reported at 1, 3, and 6 weeks. In some cases, media may be incubated for up to 8 weeks and if positive, a supplemental report will be issued.
- Identification is reported within 3 days to 2 weeks, depending on the method(s) used.
Lab Department
Infectious Disease, Mycobacteriology
Synonyms
NAAT with AFB3, NAAT with AFB7 and AFB4, TB rule out, AFB2C, NAAT, culture, smear, identification, nucleic acid amplification testing, reverse hybridization testing, NTM
Related Tests
NAAT is a direct TB test component of AFB1; AFB3 is similar to AFB1, except it is primarily for NTM, since the TB NAAT test is not performed; AFB4 is the identification component of AFB1.
TB NAAT: FDA approved for sputum, validated for some other sources.
Smear and culture (AFB7): Reference method, no special licensing required.
Identification (AFB4): waiver/single use permit is required for Identification of AFB for NYS isolates