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Serum or Plasma Substance Concentration by Immunoassay (e.g., for C-reactive protein or similar inflammatory marker)

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

This test measures the level of a substance in your blood that can signal inflammation or immune system activity. It may be used to assess conditions like infections, autoimmune diseases, or other health concerns.

Quick summary

["Helps identify inflammation or immune responses in your body."]

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

Key facts at a glance

LOINC
25824-4
Short code
S aureus Etx C IgE Qn
Synonyms
S aureus Etx C IgE Qn
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 Is This Test Measuring?

The test detects a specific protein or substance in your blood that is often elevated during inflammatory processes. This could include markers like C-reactive protein (CRP) or others used to monitor immune activity. The exact substance may vary based on clinical context and lab protocols.

Why Might I Need This Test?

Your healthcare provider may order this test to check for signs of inflammation, infections, or autoimmune conditions. It can also help monitor treatment responses or track disease progression in certain situations.

Common Uses in Healthcare

This test is often used in diagnosing or managing conditions such as infections (e.g., bacterial or viral), inflammatory diseases (e.g., rheumatoid arthritis), or evaluating responses to treatments like antibiotics or steroids.

What to Expect Before the Test

No special preparation is typically required, but you may be asked to fast for a few hours if the test involves a specific analyte sensitive to food intake. Always follow your healthcare provider’s instructions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Inflammatory Marker (Serum/Plasma)

Frequently asked questions

What does a high or low result mean?
A high result may suggest inflammation, infection, or an immune response, while a low result might indicate a lack of such activity. Your results will be interpreted by your healthcare provider in the context of your overall health and symptoms.
How often will I need this test?
The frequency depends on your medical condition and treatment plan. Your doctor will determine how often this test should be repeated, whether it’s part of routine monitoring or for specific follow-ups.
Can I eat or drink before this test?
Check with your healthcare provider for specific instructions, but generally, you can eat and drink normally unless directed otherwise, as this test does not require fasting.
  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