Prothrombin Time
Also known as: PT
Use
Prothrombin Time (PT) is an initial test for suspected bleeding disorders. It aids in evaluating liver function, detecting factor deficiencies, and diagnosing conditions associated with prolonged clotting times such as Hemophilia and uncommon factor deficiencies. It measures the time it takes for blood to clot, which is critical for identifying disorders that affect blood coagulation and monitoring blood-thinning therapies.
Special Instructions
This test is approved by New York state, which ensures compliance with stringent clinical laboratory testing regulations. Care must be taken to submit separate specimens when multiple tests are ordered to prevent sample contamination or depletion.
Limitations
The Prothrombin Time test has limitations in that it cannot determine specific factor deficiencies alone and may not reflect all coagulation abnormalities. Results can be affected by improper sample collection, such as clotted or hemolyzed specimens, or using incorrect anticoagulants. The stability of the specimen is also crucial for accurate results; ambient or refrigerated samples are unacceptable as only frozen samples maintain stability for up to two weeks.
FDA ApprovedNew York Approved
Methodology
Automated Analyzer (Coagulation)
Biomarkers
LOINC Codes
- 5902-2
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
0.5 mL
Container
Light blue (sodium citrate) tube, transfer to ARUP standard transport tube
Collection Instructions
Collect using light blue (sodium citrate) tube according to hemostasis/thrombosis guidelines. Transfer to ARUP standard transport tube.
Storage Instructions
CRITICAL FROZEN. Do not allow the sample to thaw during storage or transport.
Causes for Rejection
Serum or EDTA plasma, clotted or hemolyzed specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | Unacceptable |
| Frozen | 2 weeks |