Skip to content

Serum or plasma concentration of substance (unspecified analyte) measured by immunoassay

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of a specific substance in your blood, using a blood sample drawn from a vein. The method involves detecting the substance with a highly sensitive antibody-based test.

Quick summary

["This test helps assess levels of certain proteins, hormones, or other substances in your blood that may be linked to health conditions."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
78990-9
Short code
FAD SerPl-sCnc
Synonyms
FAD 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

What This Test Measures

The test detects the presence and concentration of a particular substance in your serum or plasma. The immunoassay method is used to identify the substance by binding it to a labeled antibody, which then triggers a measurable reaction. This allows for precise quantification of the analyte, though the exact substance remains unspecified in this test description.

Why It’s Done

Your healthcare provider may order this test to diagnose or monitor conditions related to abnormal levels of specific proteins, hormones, or other substances in the blood. For example, it could be used to check for infections, autoimmune diseases, or hormonal imbalances.

Sample Collection

A blood sample is collected from a vein in your arm by a healthcare professional. The blood is then processed to separate serum or plasma, which is sent to the lab for testing. You may feel a slight pinch when the needle is inserted, but the procedure is generally quick and painless.

Preparation

No special preparation is typically required for this test. However, you may be advised to avoid certain medications or foods for 24 hours before the test if your provider has specific instructions. Always follow your provider’s guidance.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Frequently asked questions

How might abnormal results affect my health?
Abnormal results could indicate underlying health issues, such as infections, inflammatory conditions, or disorders affecting the production or regulation of the measured substance. For instance, elevated levels might suggest an overactive immune response or hormonal imbalance, while low levels could point to deficiencies or dysfunctions in organ systems.
What does it mean if my results are within normal range?
If your results fall within the expected range, it generally means the measured substance is functioning as it should within your body. However, this does not rule out other potential health concerns—your provider will consider the full clinical picture when interpreting results.
How soon will I get my results?
Results are typically available within 1 to 3 business days, depending on lab processing times. Your healthcare provider will contact you to discuss the findings and next steps, such as additional testing or follow-up care.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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