ARUP's Laboratory Test Directory

Mycobacterium tuberculosis Amplified Direct Detection : 0060095
[ image for: Additional Technical Information]
Additional Technical Information
  


Mnemonic: MC MTD

Methodology: Qualitative Transcription Mediated Amplification (Gen-Probe®)
Performed: Sun-Fri
Reported: 1-3 days
Specimen Required: Patient Prep: Three sputum specimens should be collected at 8-24 hour intervals (24 hours when possible) and should include at least one first morning specimen. An individual order must be submitted for each specimen.

Collect: Respiratory specimens: Bronchoalveolar lavage (BAL), pleural fluid, sputum. Respiratory specimen processed by NaOH NALC digestion decontamination procedure. Unprocessed specimen is preferred.

Specimen Preparation: Unprocessed specimens: Transport 5-10 mL respiratory specimen in a sterile container. (Min: 1 mL). Label as unprocessed.
Processed specimens: Transport 2-5 mL digested/decontaminated respiratory specimen in a sterile container. (Min: 1 mL). Identify method used for digestion and provide smear results.
Place each specimen in an individually sealed bag.

Storage/Transport Temperature: Refrigerated.

Remarks: Specimen source required. To perform this test it is essential to know whether or not the submitted specimen has been processed (digestion and decontamination procedure). If it has, smear results must be provided as a comment on the test order or requisition. Delayed turnaround time will occur when the required information is not provided.

Unacceptable Conditions: Grossly bloody specimens. Pericardial fluid, or tissue (fresh or paraffin block). Specimens processed by Alpha-Tec Systems. For CSF refer to Mycobacterium tuberculosis Amplified Detection, CSF (ARUP test code 0060063).

Stability (collection to initiation of testing): Unprocessed: Ambient: Unacceptable; Refrigerated: 1 week; Frozen: 2 weeks
Processed: Ambient: Unacceptable; Refrigerated: 72 hours; Frozen: 2 weeks
Reference Interval:
Negative - No Mycobacterium tuberculosis complex rRNA detected by transcription-mediated amplification.
Interpretive Data: The MTD test is specific for, but does not differentiate among, members of the M. tuberculosis complex. M. celatum and M. terrae-like organisms will cross react if present at concentrations higher than 30 CFU/test. However, those species are rare clinical isolates. Specimens with high levels of nontuberculosis mycobacteria (greater than 1,000,000 cells/test) may cause low-level positive MTD results when M. tuberculosis complex is not present. This test is FDA cleared but is not labeled for use with pleural fluid specimens.
Note: Unprocessed, refrigerated respiratory specimens are the preferred submissions for this assay.  However, processed respiratory specimens will be accepted if refrigerated less than 72 hours and smear result is provided.

The manufacturer has not determined the efficacy of this test when performed on pleural fluid. The performance characteristics of this test were determined by ARUP Laboratories.

For CSF specimens refer to Mycobacterium tuberculosis Amplified Detection, CSF (0060063).
CPT Code(s): 87556
Cross References: AFB by Amplified Detection (Mycobacterium tuberculosis Amplified Direct Detection) , Mycobacterium tuberculosis Detection, NAA (Mycobacterium tuberculosis Amplified Direct Detection)