High-Resolution Mutational Analysis of Mycobacterium tuberculosis (MTB) KatG Gene
This test checks for specific genetic changes in the KatG gene of *Mycobacterium tuberculosis*, a bacterium responsible for tuberculosis. It helps determine if the bacteria may be resistant to certain first-line antibiotics.
["Assists in guiding antibiotic treatment for tuberculosis by identifying genetic resistance patterns."]
Key facts at a glance
- LOINC
- 46246-5
- Short code
- M TB katG INH high res mut Islt/Spm
- Synonyms
- M TB katG INH high res mut Islt/Spm
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- molgen
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your healthcare provider may order this test if you have tuberculosis symptoms, such as persistent cough, fever, or weight loss, and if standard antibiotics aren’t working as expected. It’s also used in patients with suspected drug-resistant tuberculosis to tailor treatment more effectively.
What to Expect Before the Test
No special preparation is needed. You’ll likely provide a **whole blood sample** (taken from a vein) or a **sputum sample** (from coughing into a container). If using blood, you may experience a brief pinch or discomfort at the needle site.
What the Test Measures
The test looks for mutations in the KatG gene, which encodes an enzyme (katG) critical for the breakdown of the antibiotic isoniazid. Mutations in this gene can make the bacteria resistant to isoniazid, a key antibiotic in tuberculosis treatment.
How Results Are Used
Results help healthcare providers decide if you need alternative antibiotics or a combination of drugs. This can shorten treatment duration or prevent drug resistance from developing.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Identifying KatG mutations is crucial for managing drug-resistant tuberculosis. Early detection allows for more targeted therapy, reducing treatment failure, relapse risks, and potential spread of resistant strains. This test supports both initial diagnosis and ongoing monitoring of treatment efficacy.
Short name
MTB KatG Mutation Screen
Frequently asked questions
What does a positive result mean?
Will this test change my treatment plan?
How long does it take to get results?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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