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Immunoglobulin G (IgG) Subclass 1 and 2 Quantification with Electrophoresis

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

This test measures the levels of specific types of Immunoglobulin G (IgG) antibodies in your blood, which are part of your immune system. IgG subclasses play different roles in immunity, and their balance is important for effective immune responses.

Quick summary

["Understanding your IgG subclass levels can help identify immune system imbalances or deficiencies."]

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

Key facts at a glance

LOINC
44006-5
Short code
COXAB
Synonyms
C burnet Ph1 + Ph2 IgG+IgM Ser-Imp
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) or red-top tube
Units
N/A
Ref low
0
Ref high
1
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Immunofluorescence Assay (IFA)
CPT
86638
SNOMED
122450004
Specimen volume
1-2 mL serum
Stability
Stable for 7 days at 2-8°C; for extended storage, freeze at -20°C or below
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
48–96 hours
Order
routine

Why IgG Subclasses Matter in Immunity

IgG antibodies are the most abundant type of antibody in your blood and provide long-term immunity. They are divided into four subclasses (IgG1, IgG2, IgG3, IgG4), each with distinct functions. IgG1 and IgG2 are particularly important for fighting bacterial infections and responding to vaccines. Abnormal levels of these subclasses can indicate immune system disorders, such as hypogammaglobulinemia or certain autoimmune diseases.

How the Test Works

This test uses **electrophoresis**, a method that separates proteins in your blood based on size and charge. The serum is analyzed to quantify IgG1 and IgG2 concentrations, which helps determine their relative proportions and overall levels.

Common Conditions Affecting IgG Subclasses

Low levels of IgG1 or IgG2 may be linked to recurrent infections, poor vaccine responses, or immune system disorders like Common Variable Immunodeficiency (CVID). High levels could suggest chronic inflammation or certain autoimmune conditions. Your healthcare provider may recommend this test if you have frequent infections, unexplained fatigue, or symptoms of immune dysfunction.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re nervous, let your healthcare provider know—they can help make the process more comfortable.

Reference range

Phase 1 IgG: <1:200 (negative); Phase 2 IgG: <1:200 (negative); Phase 1 IgM: <1:50 (negative); Phase 2 IgM: <1:50 (negative). Titers ≥1:200 for Phase 1 IgG suggest chronic Q fever; Phase 2 IgG ≥1:200 with Phase 2 IgM positive suggests acute Q fever.N/A

Specimen: serum

No fasting required. Patients should inform their healthcare provider of any recent antibiotic use, as early antibiotic therapy may delay or alter antibody response. Avoid testing during the first 7-10 days of symptom onset, as antibodies may not yet be detectable.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG subclass 1 & 2 levels (electrophoresis)

Frequently asked questions

Will I need to fast before this test?
No fasting is required for this blood test. However, if you’re on blood thinners or have a history of bleeding disorders, your provider may ask you to avoid certain medications for a day or two before the test.
What if my IgG subclass levels are outside the normal range?
If your results are abnormal, your healthcare provider will discuss them with you. Low levels may mean you have an immune deficiency that could affect your ability to fight infections. High levels might suggest chronic inflammation or other underlying conditions. Follow-up testing or treatments may be recommended based on your symptoms and test results.
Can I take my usual medications before the blood draw?
Yes, you can take your usual medications as scheduled, unless your provider specifically instructs otherwise. If you’re unsure, ask your healthcare provider before the test.
  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