Serum or plasma substance concentration for sodium (hyponatremia/hypernatremia screening)
This test measures the amount of sodium in your blood, which helps balance fluids and electrolytes in your body. Sodium is crucial for nerve and muscle function, as well as maintaining proper fluid balance.
["Sodium levels help doctors diagnose conditions like dehydration, heart or kidney problems, or excessive sweating."]
Key facts at a glance
- LOINC
- 102919-8
- Short code
- S aureus Etx A IgE RAST
- Synonyms
- S aureus Etx A IgE RAST
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- rast
- CPT
- 84484
- SNOMED
- 302774002
- 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 Is This Test Done and What Can the Results Tell My Doctor About My Health?
Your doctor may order this test if you have symptoms like confusion, fatigue, swelling, or irregular heartbeat. It’s also used to monitor conditions like heart failure, kidney disease, or certain hormonal imbalances.
What to Expect Before the Test and How Should You Get Ready for Your Appointment?
No special preparation is needed. You may drink water before the test, but avoid excessive salt intake 24 hours beforehand if instructed. Bring any medications you’re taking to your doctor’s office.
What Happens During the Test and How Long Will the Whole Procedure Usually Take?
A healthcare provider will draw blood from a vein in your arm. You may feel a small pinch, but it usually takes only a few minutes. The blood sample is sent to a lab for analysis.
What Are the Results and When Can You Expect Your Doctor to Go Over Them With You?
Results are typically reported as a numerical value (in mmol/L or mg/dL) compared to a reference range. Your doctor will interpret the results in relation to your health and symptoms.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low sodium levels (hyponatremia) can cause headaches, nausea, confusion, or seizures. High sodium levels (hypernatremia) may lead to thirst, dry mouth, or muscle spasms. Both can indicate serious underlying conditions like kidney disease, heart problems, or excessive fluid loss.
Short name
Sodium Level
Frequently asked questions
How long does it take to get my results?
Can I eat or drink anything before the test?
Does this test require fasting?
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