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Serum or Plasma Substance Concentration by Immunoassay (e.g., for Specific Protein or Antibody)

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

This test measures the amount of a specific substance (such as a protein or antibody) in your blood, either serum or plasma, using an immunoassay method.

Quick summary

["Helps identify levels of important substances that may affect health or indicate certain conditions."]

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

Key facts at a glance

LOINC
87345-5
Short code
SVA Spec Ql Cult
Synonyms
SVA Spec Ql Cult
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
organism-specific-culture
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

An immunoassay detects and quantifies a particular substance in your blood. This method often uses antibodies to bind specifically to the target substance, allowing for precise measurement. The test may be used for a wide range of analytes, including hormones, proteins, or antibodies, depending on clinical need.

Why It’s Ordered

Doctors may order this test to diagnose or monitor conditions like infections, autoimmune diseases, kidney function, or certain cancers. It can also help track treatment responses or screen for genetic or metabolic disorders.

Sample Collection and Preparation

Blood is drawn from a vein, typically in your arm. The sample is then processed into either serum (after clotting) or plasma (anticoagulated blood). This test does not require fasting unless specified by your healthcare provider.

Common Uses in Healthcare

This test is versatile and can be used for screening, diagnosing, or managing conditions such as thyroid disorders, immune system disorders, or monitoring medications that affect protein levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Protein/Antibody Level Test

Frequently asked questions

What does a high or low result mean?
A high or low result depends on the specific substance being tested. Your doctor will interpret the results in relation to your symptoms and medical history. For example, elevated protein levels might suggest a condition like multiple myeloma, while low levels could indicate malnutrition or kidney problems.
Does this test require fasting?
Not always. Some tests may require fasting, but others do not. Always follow your healthcare provider’s instructions for sample collection. If fasting is needed, avoid eating or drinking (except water) for a specified period before the test.
How long will results take?
Results can typically be available within a few days to a couple of weeks, depending on the lab’s processing time and whether additional testing (like confirmatory assays) is needed. Your doctor will contact you once results are ready.
  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