Clot Formation Time Using Kaolin Induced Partial Thromboplastin (KPTT) with Blood Sample
This test measures how long it takes for your blood to form a clot when exposed to kaolin, a substance that triggers clotting. It helps assess your blood’s ability to clot under certain conditions.
["Understanding your blood’s clotting response can help identify bleeding or clotting disorders."]
Key facts at a glance
- LOINC
- 96690-3
- Short code
- Clot Form Kaolin Ind Pnl Bld MicrVisc
- Synonyms
- Clot Form Kaolin Ind Pnl Bld MicrVisc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- microviscometry
- 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 This Test Measures
The test uses kaolin to activate your blood’s clotting pathway. After mixing the blood sample with kaolin, the time until a visible clot forms is recorded. This time reflects how efficiently your blood clots under these conditions.
Why It’s Done
Your doctor may order this test if you have symptoms like excessive bleeding, unexplained bruising, or a history of clotting disorders. It can also be part of evaluating inherited bleeding conditions or monitoring certain treatments.
How the Test Works
A small amount of your whole blood is mixed with kaolin in a lab tube. The time taken for the blood to form a clot is measured and compared to expected values for your age and health status.
Preparation and Sample Collection
No special preparation is needed. Blood is drawn from a vein, similar to other blood tests. If you’re on blood-thinning medication, let your doctor know before the test.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormally long clot times may indicate bleeding disorders, such as hemophilia or von Willebrand disease. Short or inconsistent times could suggest clotting disorders or interference from medications. This test is particularly useful for diagnosing inherited clotting deficiencies or monitoring treatment effects.
Short name
KPTT (Kaolin Clot Time)
Frequently asked questions
When might I need this test?
What does a normal result mean?
Can this test be affected by medications?
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