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Alpha-Internexin IgG Antibody, Serum — Qualitative

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

A qualitative serum test that detects IgG antibodies against alpha-internexin, a protein associated with some cases of myasthenia gravis.

Quick summary

["A positive result may support myasthenia gravis when considered with symptoms and other antibody tests, but it does not confirm the diagnosis by itself."]

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

Key facts at a glance

LOINC
96483-3
Short code
Alpha-internexin IgG Ser Ql CBA IFA
Synonyms
Alpha-internexin IgG Ser Ql CBA IFA
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
44
Ref high
147
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
cba-ifa
CPT
84075
SNOMED
27550007
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?

This blood test checks for IgG antibodies directed against alpha-internexin, a nervous-system protein. It is sometimes used when myasthenia gravis is suspected.

Why might I need this test?

Your clinician may order it to help evaluate muscle weakness, eyelid drooping, swallowing difficulty, or other symptoms that can occur with myasthenia gravis. Results are usually interpreted together with the examination and other laboratory tests.

How is the test performed?

A blood sample is collected, and the serum is tested using an immunoassay to determine whether alpha-internexin IgG antibodies are present. This is primarily a qualitative test.

How do I prepare for the test?

No special preparation is usually required. Follow any instructions from the laboratory, and tell your clinician about medicines you take because some treatments can affect antibody test results.

Reference range

Adult: 44-147 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Alpha-internexin IgG antibody

Frequently asked questions

Does a positive result mean I have myasthenia gravis?
Not by itself. A positive result can support myasthenia gravis, but your clinician must interpret it with your symptoms, examination findings, and other tests.
What if the test is negative?
A negative result means alpha-internexin IgG antibodies were not detected. Myasthenia gravis can still be possible if another subtype of the disease is suspected, so other testing may be needed.
Is this the same as an acetylcholine receptor antibody test?
No. This test looks for antibodies to alpha-internexin, while an acetylcholine receptor antibody test looks for a different antibody associated with myasthenia gravis. Both may be included in the evaluation.
  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