Prothrombin Time (PT), Plasma
Use
This test is primarily used for screening to identify a deficiency of one or more of the clotting factors of the extrinsic coagulation system such as factors I, II, V, VII, and X. It is helpful in detecting hereditary deficiencies or acquired conditions like liver disease, vitamin K deficiency, or the presence of specific factor inhibitors. Additionally, it is used for monitoring patients on oral anticoagulant therapy, ensuring they remain within a safe therapeutic range.
Special Instructions
Prothrombin time should be used in conjunction with the patient's medication history, as heparin or Coumadin therapy must be noted for accurate interpretation. This test is only orderable as part of a profile or reflex.
Limitations
The PT test may not differentiate between factor deficiencies and inhibitor presence, requiring further testing like mixing studies for accurate diagnosis. Lipemic specimens can interfere with clot detection mechanisms, and hence grossly lipemic samples should be rejected. Prothrombin time mixing studies are of no value when patient PT values are within the normal range.
FDA ApprovedNew York Approved
Methodology
Automated Analyzer (Coagulation)
Biomarkers
LOINC Codes
- 34528-0
- 6301-6
- 5902-2
Result Turnaround Time
1-5 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
Not provided
Minimum Volume
Not provided
Container
Plasma Na Cit
Patient Preparation
Heparin or Coumadin therapy should be noted
Causes for Rejection
Gross hemolysis, Gross lipemia, Gross icterus
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 14 days |