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Opsonization Protein Screening (Microbiological Activity)

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

This test measures your body’s ability to tag harmful bacteria or viruses for immune cells to destroy. It helps assess immune function, especially in conditions like infections or immune deficiencies.

Quick summary

["Helps identify if your immune system is working as it should to fight infections."]

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

Key facts at a glance

LOINC
91768-2
Short code
O+P Spt Micro
Synonyms
O+P Spt Micro
Category
chemistry
Sample
sputum
Container
Sterile sputum container
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
microscopy-light
CPT
85610
SNOMED
396252006
Specimen volume
3-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
TAT
4–24 hours
Order
routine

What This Test Measures

Opsonization involves proteins in your blood that coat pathogens (like bacteria) to make them easier for white blood cells to recognize and eliminate. This test evaluates the presence and activity of these proteins in your serum or plasma.

Why It Matters in Your Health

Low opsonization activity may indicate weakened immune responses, increasing risk for infections. It’s often used in diagnosing or monitoring immune-related conditions.

When You Might Need This Test

Your doctor may order this test if you have frequent infections, an immune disorder, or if you’re undergoing treatment that could affect your immune system.

Sample Collection and Preparation

A blood sample is drawn from a vein in your arm. The sample is processed to separate serum or plasma for testing. This test does not require fasting or special preparation beyond standard blood draws.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: sputum

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Opsonization Test

Frequently asked questions

What does a low or high result mean?
A low result suggests your immune system may struggle to effectively tag pathogens for destruction, which could require further evaluation of immune function or treatment adjustments.
This test is not a standalone diagnosis but may guide additional testing if infections persist or immune issues are suspected.
Coverage depends on your insurance plan and clinical indication. Check with your provider to confirm if this test is approved for your specific situation.
How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on lab processing times and your healthcare provider’s workflow.
  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