Genetic Mutation Test for Calcium Channel Subunit Alpha-1S (CACNA1S)
This test checks for specific changes (mutations) in the gene responsible for encoding the calcium channel subunit alpha-1S, which plays a role in muscle and nerve function.
["Helps identify potential genetic causes of muscle-related disorders."]
Key facts at a glance
- LOINC
- 21645-7
- Short code
- CACNA1S
- Synonyms
- CACNA1S gene Mut Tested Bld/T
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA tube (lavender top) for whole blood; sterile container for tissue specimens
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- molgen
- CPT
- 81404
- SNOMED
- 5304006
- Specimen volume
- 3-5 mL whole blood in EDTA tube; or tissue specimen as appropriate
- Stability
- Whole blood stable at room temperature for 24 hours; refrigerated (2-8°C) for 7 days; frozen at -20°C or below for long-term storage. DNA extracted from samples stable for years when stored properly.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 168–720 hours
- Order
- routine
Why This Test Might Be Ordered
Your healthcare provider may recommend this test if you have symptoms like unexplained muscle weakness, stiffness, or cramps, or if family members have a history of muscle disorders linked to genetic mutations in the CACNA1S gene. It may also be part of genetic testing for conditions like periodic paralysis or other myopathies.
What to Expect During the Test
A small blood sample will be taken from your arm. The sample is then sent to a lab for genetic analysis to detect mutations in the CACNA1S gene. Results are typically available within a few weeks.
Understanding Your Results
Results can be normal (no mutations found) or abnormal (mutations detected). Abnormal results may indicate a genetic predisposition to muscle disorders. Discuss your results with your healthcare provider for personalized guidance.
Preparation and Considerations
No special preparation is needed for this blood test. If you are pregnant, have an infection, or are on certain medications, inform your healthcare provider before the test.
Reference range
Nominal result: Negative (no pathogenic CACNA1S mutations detected). Positive indicates presence of one or more pathogenic mutations associated with malignant hyperthermia susceptibility, hypokalemic periodic paralysis, or other CACNA1S-related disorders.N/A
No special patient preparation required. Patient should be informed about genetic testing implications and provide informed consent prior to sample collection. Genetic counseling may be recommended.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CACNA1S Gene Mutation Test
Frequently asked questions
What does a positive result mean?
Will this test be covered by insurance?
Can I fast before this test?
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