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Glial Fibrillary Acidic Protein (GFAP) by Western Blot (Qualitative)

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

This test detects the presence of Glial Fibrillary Acidic Protein (GFAP), a marker protein found in certain types of brain cells called astrocytes. It is used to help diagnose conditions affecting the brain or spinal cord.

Quick summary

["GFAP Western Blot helps identify potential brain injuries or diseases by checking for specific protein markers in a blood sample."]

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

Key facts at a glance

LOINC
82444-1
Short code
Glial nuc type 1 Ab Ser Ql Line blot
Synonyms
Glial nuc type 1 Ab Ser Ql Line blot
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
line-blot
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 recommend this test if you have symptoms like sudden changes in mental status, severe headaches, confusion, seizures, or neurological issues. It could also be used in cases of suspected traumatic brain injury, stroke, or other neurological conditions where GFAP levels might be elevated.

What to Expect Before the Test

No special preparation is usually needed. You may have a simple blood draw, similar to other routine blood tests. If you are on blood-thinning medications, let your provider know before the test.

What the Test Results Mean

A positive result (detecting GFAP) may suggest damage to brain cells, such as in conditions like brain hemorrhage, brain tumors, or certain types of encephalitis. However, results alone do not diagnose a condition; they are used alongside clinical findings and other tests.

Common Conditions Evaluated

This test is often used in conjunction with other diagnostic tools to evaluate conditions such as traumatic brain injury, subarachnoid hemorrhage, brain tumors, or other neurological disorders that may involve glial cell damage.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: GFAP Role and Limitations

Short name

GFAP Western Blot (Qual)

Frequently asked questions

What does a positive result mean?
A positive GFAP Western Blot result indicates the presence of GFAP protein in your blood, which can suggest damage to astrocytes (a type of brain cell). This can be associated with conditions like brain injury, stroke, or certain infections. However, it is not definitive on its own and should be interpreted with clinical context and other diagnostic findings.
Can this test detect all brain conditions?
No, this test is not a comprehensive brain scan. It helps identify specific conditions involving glial cell damage but may not detect all neurological issues. It is often used alongside other tests, imaging, and clinical evaluations for a complete diagnosis.
How soon will I get my results?
Results from this qualitative test are typically available within a few days to a week, depending on the laboratory. Your healthcare provider will discuss the results with you in detail and explain next steps.
  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