Serum/plasma substance concentration (unspecified analyte) measured by immunoassay
This test measures the level of a specific substance in your blood, likely related to protein or antibody detection, using an immunoassay method.
["Your blood test helps assess certain protein or antibody levels that may indicate health conditions or immune responses."]
Key facts at a glance
- LOINC
- 61018-8
- Short code
- O2 VFr/PPres Gas DS
- Synonyms
- O2 VFr/PPres Gas DS
- 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
What This Test Measures
This test detects the presence and amount of a particular substance in your blood, often used to identify proteins, antibodies, or other biomarkers. The exact analyte isn’t specified, but it’s typically measured through an immunoassay, which detects specific molecules like hormones, infections, or immune markers.
Why It’s Done
Your healthcare provider may order this test to diagnose or monitor conditions such as infections, autoimmune diseases, or other health concerns affecting protein levels in your blood.
Sample Collection and Preparation
A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate serum or plasma, which is sent to a lab for testing. This process helps ensure accurate measurement of the substance in question.
What to Expect Before the Test
No special preparation is usually required, but you may be asked to fast or avoid certain medications for a few hours before the test, depending on the specific instructions from your doctor.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated or low levels of this substance can signal underlying health issues, such as infections, inflammation, autoimmune disorders, or other metabolic conditions. Results are interpreted in the context of your medical history, symptoms, and other lab findings to guide diagnosis and treatment.
Frequently asked questions
Why might my doctor recommend this test?
What does a high or low result mean?
How often will I need 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