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Serum or plasma mass concentration of immunoglobulin G (IgG) fragments, specifically the F(ab')₂ fragment

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

This test measures a specific portion of your immune system’s antibody protein (IgG) that may help assess immune function or detect certain immune-related conditions.

Quick summary

["This test helps evaluate how your immune system breaks down antibodies or identifies fragments that could signal immune disorders."]

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

Key facts at a glance

LOINC
27139-5
Short code
Deprecated S pneum7f IgG Ser-mCnc
Synonyms
Deprecated S pneum7f IgG Ser-mCnc
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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

Why This Test Might Be Ordered

Your healthcare provider may order this test if you have symptoms or conditions linked to immune system dysfunction, such as chronic infections, autoimmune diseases, or certain blood disorders. It may also be used in research or specialized diagnostic contexts where specific antibody fragments are of interest.

What to Expect Before the Test

No special preparation is typically needed. You may have a blood sample drawn from a vein in your arm. If you’re on blood-thinning medication, let your provider know before the test.

What the Results Mean

Results may indicate abnormal fragmentation of IgG, which could suggest conditions like immune complex diseases, certain infections, or immune system dysregulation. Your provider will interpret results in the context of your overall health and symptoms.

Common Conditions Monitored

This test is less commonly used in routine clinical practice but may be part of specialized evaluations for conditions like chronic immune activation, certain lymphoproliferative disorders, or research studies focused on antibody behavior.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Limited Routine Use

Short name

IgG F(ab')₂ fragment level

Frequently asked questions

What does a high or low level of IgG fragments mean?
High levels might suggest excessive antibody breakdown or immune activation, while low levels could indicate impaired immune function or specific genetic or acquired conditions affecting antibody metabolism. Always discuss results with your healthcare provider.
How often is this test repeated?
Since this test is not standard in most clinical settings, repeat testing is uncommon unless part of a specialized study or ongoing monitoring for a known condition. Your provider will guide frequency based on your care plan.
Can diet or medications affect this test?
Dietary factors or medications that affect immune function (e.g., steroids, immunosuppressants) may indirectly influence antibody levels, but direct effects on IgG fragment measurements are not well-documented. Always follow your provider’s advice regarding medication use before testing.
  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