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Nucleic Acid Probe for Mycobacterium tuberculosis (MTB) Detection in Sputum

Published: August 9, 2026Updated: August 16, 2026

This test detects genetic material from *Mycobacterium tuberculosis* (MTB), the bacterium responsible for tuberculosis (TB), in your sputum. It helps confirm whether you have active TB infection.

Quick summary

["This test can quickly identify TB bacteria even if other tests are inconclusive, improving early diagnosis and treatment planning."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
14559-9
Short code
M tb DNA Plr Ql NAA+probe
Synonyms
M tb DNA Plr Ql NAA+probe
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

How the Test Works

Your sputum sample is analyzed using a specialized probe that targets unique genetic sequences of MTB. The test detects these sequences by binding to them, indicating the presence of the bacterium. This method is highly sensitive and specific for TB.

Sample Collection

You’ll need to provide a sputum sample, typically collected by coughing deeply into a sterile container. This is often done in a healthcare setting to ensure proper technique and sample quality.

What to Expect Before the Test

No special preparation is needed, but you may be asked to avoid certain medications (like some antibiotics) that could interfere with results. If you’re unsure, discuss this with your provider.

Possible Results

A positive result means the test detected MTB DNA in your sample, strongly suggesting active TB. A negative result means no MTB DNA was found, but further testing or follow-up may still be needed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

MTB DNA Probe Test

Frequently asked questions

Why was I asked to take this test?
Your healthcare provider may recommend this test if you have symptoms like persistent cough, fever, or weight loss, or if you’ve been exposed to TB. It’s also used in screening for latent TB infection or when other tests are inconclusive.
What does a positive result mean?
A positive result strongly suggests you have active TB and will need treatment with antibiotics to kill the bacteria. Follow your provider’s instructions carefully, as treatment typically involves multiple medications for several months.
Can I get TB from this test?
No, the test itself does not expose you to TB. The sputum sample is processed in a way that prevents contamination. If you’re concerned about exposure, discuss it with your healthcare provider—they can guide you on precautions.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy