Mycobacterium Tuberculosis Direct Test

CERNER / EPIC MNEMONIC:

AFB MTD

POE DESCRIPTION:

AFB MTD

CPT CODE: 87556
CDM NUMBER: 3421131
TEST INFORMATION:

Detection of presence (positive) or lack of presence (negative) of Mycobacterium tuberculosis complex rRNA.

[Note: The Gen-Probe¿ amplification system (MTD) is specific for, but does not differentiate among, members of the M. tuberculosis complex.]

DAYS PERFORMED:

Daily.  Sent to IDPH if AFB Smear is positive.

TURNAROUND TIME:

3-5 days

SPECIAL INSTRUCTIONS:

Transport specimen to laboratory immediately.  If delay, store specimen at 2°-8°C.

CONTAINER TYPE: Sealed sterile container, no preservative
SPECIMEN REQUIREMENTS:

Undigested sputum (induced or expectorated), Bronchial specimens (bronchoalveolar lavage or bronchial aspirate), tracheal aspirate, pleural fluids.

REJECTION CRITERIA:

1. Specimen other than sputum (induced or expectorated), bronchial specimens (bronchoalveolar lavages or bronchial aspirates), tracheal aspirates or pleural fluids.

2. Specimen from previous MTD test 'positive' (without written justification from physician).

3. Patient specimens with a ''negative'' MTD result will only be tested three times in a 90-day period.

4. Specimens not stored at 2° to 8°C before transport.

5. Specimens older than 7 days.

6. Specimen not labeled.

7. Grossly bloody specimen.

MINIMUM VOLUME:

0.5 mL

REFERENCE RANGE: Not detected.
METHODOLOGY: The Gen-Probe¿ amplification system amplifies a specific ribosomal RNA (rRNA) target via DNA intermediates.¿ Detection of the amplified rRNA sequence (amplicon) is achieved using nucleic acid hybridization.¿ The chemiluminescent single-stranded DNA probe is complementary to the amplicon.¿ The labeled DNA probe combines with the amplified ribosomal RNA to form a stable RNA:DNA hybrid.¿ The selection reagent differentiates hybridized from non-hybridized probe.¿ The labeled RNA:DNA hybrids are measured in a luminometer.
REFERRAL LABORATORY:

Commercial Laboratory

ADDITIONAL INFORMATION:

Patients with respiratory specimens that test AFB smear positive will require on AFB MTD test.

LAST UPDATED:

5-27-2014

TEST SYNONYM(S):Mybacterium Tuberculosis Direct Test, Amplified (MTD