Serum or plasma concentration of a substance (unspecified analyte) measured by immunoassay
This test measures the amount of a specific substance in your blood, drawn from either serum or plasma. It helps assess levels of certain proteins, hormones, or other chemicals in your body.
["This test helps doctors monitor conditions affecting blood chemistry or detect certain health issues."]
Key facts at a glance
- LOINC
- 51611-2
- Short code
- MTX 48h p SerPl-sCnc
- Synonyms
- MTX 48h p SerPl-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 Might Be Ordered
Your healthcare provider may recommend this test if they suspect an imbalance in certain substances in your blood. This could be due to conditions like infections, hormonal imbalances, kidney or liver problems, or other metabolic disorders. It may also be part of routine screening or monitoring for chronic conditions.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it involves blood drawn from an empty stomach. Avoid smoking or consuming alcohol for a few hours beforehand. Wear comfortable clothing and plan to rest after the draw.
What Happens During the Test
A healthcare professional will insert a small needle into a vein in your arm. Blood will be collected into a tube. The process usually takes a few minutes. You may feel a brief pinch, but it’s quick and rarely causes discomfort. The blood sample is then sent to a lab for analysis.
What to Expect After the Test
You may experience mild bruising, swelling, or discomfort at the injection site. Apply gentle pressure to the area for a few minutes after the needle is removed. Avoid heavy lifting or strenuous activity for a short time. Rest if you feel dizzy or lightheaded.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated or low levels of this substance can signal underlying health problems. For example, certain substances may indicate infections, autoimmune diseases, or organ dysfunction. Your provider will interpret results in the context of your medical history, symptoms, and other tests. Follow-up may include additional testing or adjustments to treatment plans.
Short name
Substance concentration test (serum/plasma)
Frequently asked questions
How long will I need to wait for results?
What does it mean if my test results are outside of normal ranges?
Can I eat or drink 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