TNNT3 Familial Mutation Analysis, Blood
A blood-based genetic test that looks for disease-causing variants in the TNNT3 gene, which is associated with certain inherited skeletal muscle disorders.
["This test can help determine whether a person or family member has a hereditary condition involving the TNNT3 gene."]
Key facts at a glance
- LOINC
- 81881-5
- Short code
- TNNT3 Fam Mut Anl Bld/T
- Synonyms
- TNNT3 Fam Mut Anl Bld/T
- Category
- thyroid
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 80
- Ref high
- 200
- Critical range
- 20 N/A – 400 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- molgen
- CPT
- 84436
- SNOMED
- 302346007
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What is this test?
This test examines DNA from a blood sample for variants in the TNNT3 gene. Changes in this gene can cause inherited skeletal muscle disorders, including certain forms of nemaline myopathy.
Why might I need this test?
A clinician may recommend this test when symptoms suggest an inherited muscle condition, especially when another family member has a related diagnosis. It may also be used to clarify a person's risk or guide testing and counseling for relatives.
How is the test performed?
A blood sample is collected, and the laboratory analyzes its DNA for clinically significant TNNT3 variants. The exact laboratory method may include gene sequencing or other genetic analysis techniques.
How do I prepare for the test?
This test usually does not require fasting or special preparation. Follow any instructions from the ordering clinician or genetic counselor, and tell the laboratory if you have had a bone marrow or blood transfusion.
Reference range
Adult: 80-200 ng/dLN/A
Take your thyroid medication after the blood draw if applicable. No fasting required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A pathogenic or likely pathogenic TNNT3 variant may support a diagnosis of an inherited skeletal muscle disorder and can have implications for relatives. A negative result does not exclude every genetic cause of muscle disease. A variant of uncertain significance is not, by itself, considered a confirmed disease-causing finding.
Short name
TNNT3 Genetic Test
Frequently asked questions
Does a positive result mean I will definitely develop symptoms?
Can this test diagnose a muscle disease on its own?
Should relatives also be tested?
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 17, 2026. · Read our editorial policy