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Mycobacterium - MTD test



Other Names Amplified Mycobacterium tuberculosis Direct Test
How to Order
Check the MTD box under the Mycobacterium Section of the General Microbiology Request Form

Primary Samples: County and State Agencies

NALC-NaOH concentrated pellets: Private Care Laboratories
Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test
Tuesdays and Thursdays on regular business days
Time to Reporting
1 to 5 working days after receipt of specimen
CPT Code

Specimen Collection Details


Primary respiratory specimens from County Health Departments are collected as per instructions at: Instructions begin on page two under "Collection Instructions."

NALC-NaOH concentrated respiratory specimens from Private Care Laboratories are submitted as per instructions at: Instructions begin at the end of page three under "Secondary Specimens."
Optimal Volume

Primary County respiratory samples:  1 – 5 ml

Private Care Lab concentrated pellets: 0.5ml – 1ml
Minimum Volume

Primary County respiratory samples:  1 ml

Private Care Lab concentrated pellets: 0.5ml
Keep specimen refrigerated (2-8C) pending transport

Primary specimens: Delivery within 5 days of collection

Concentrate pellets: Delivery within 2 days of concentration. Transport at 2 -8 C.
Note: Specimens shipped for Friday delivery must be received in lab by 12:00PM. Notify the Microbiology Section at the OSPHL if specimens will arrive later than two days after concentration or after 12:00PM.
Rejection Criteria
For concentrate pellets: Specimens not received within 3 days of concentration and/or received on a Friday after 12:00PM.
Specimens are subject to the requirements of the OSPHL Specimen Submission Policy and Criteria, available at

MTD is a Nucleic Acid Amplified Test (NAAT) that is FDA approved for respiratory samples from patients showing signs and symptoms consistent with active pulmonary tuberculosis (TB).  This test is not approved for patients who have taken medication for active TB disease in the past 12 months or for more than 7 days recently. The predictive value is related to the smear result and the prevalence of disease in a given population group. The MTD test does not distinguish between viable and non-viable organisms.

For diagnostic guidelines: