Factor VIII Inhibitor, Chromogenic Assay, Platelet-Poor Plasma
This blood test checks for antibodies that block factor VIII, a protein needed for normal blood clotting. It is performed on platelet-poor plasma using a chromogenic laboratory method.
["A positive result means that a factor VIII inhibitor is present, which may increase bleeding risk."]
Key facts at a glance
- LOINC
- 93450-5
- Short code
- Fact VIII Inhib PPP Chro-aCnc
- Synonyms
- Fact VIII Inhib PPP Chro-aCnc
- Category
- chemistry
- Sample
- plasma
- Container
- Lavender-top (EDTA) or Green-top (Heparin)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- chromo
- 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 the Test Measures
Factor VIII inhibitors are antibodies that reduce the activity of factor VIII. The laboratory mixes the patient's platelet-poor plasma with test material and measures the remaining factor VIII activity. Reduced activity can indicate the presence of an inhibitor.
How the Test Is Performed
A blood sample is collected and processed to remove platelets because platelet-related factor VIII can interfere with inhibitor testing. The resulting platelet-poor plasma is tested using a chromogenic assay, and positive results may be reported as an inhibitor titer.
Why the Test May Be Ordered
The test may be ordered for unexplained bruising or bleeding, an abnormal clotting screening test, or suspected acquired hemophilia. It is also used to monitor people with hemophilia A, in whom an inhibitor can develop and reduce the effectiveness of factor VIII treatment.
Understanding the Result
A negative result means that no significant factor VIII inhibitor was detected. A positive result means that an inhibitor was detected; the titer helps show its strength. Results should be interpreted with bleeding history, other coagulation tests, and medication use.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A confirmed factor VIII inhibitor can make blood clot less effectively and lead to spontaneous, surgical, or trauma-related bleeding. In a person with hemophilia A, it may explain poor control despite treatment. In someone without a known clotting disorder, it may suggest acquired hemophilia A, which requires prompt hematology evaluation.
Short name
Factor VIII inhibitor test
Frequently asked questions
Does a positive result mean I have hemophilia?
Is this the same test as a factor VIII activity test?
What if the result is negative but a factor VIII inhibitor is still suspected?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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