Prothrombin time (PT)
Prothrombin time is used to assess the external blood coagulation pathway state and overall coagulation potential. Helps detect clotting disorders, assess bleeding or thrombosis risk, and monitor anticoagulant therapy efficacy (e.g., warfarin).
Test composition:
- Material: venous blood
- Method: coagulometric method
- Measured indicator: blood clot formation time after thromboplastin addition
- Additional indicator: INR (International Normalized Ratio) for standardized anticoagulant monitoring
- Deviation causes: prolonged PT — factor deficiency (II, V, VII, X), liver diseases, anticoagulant intake, vitamin K deficiency. Shortened — elevated blood clotting.
Biomaterial: Venous blood
- Draw blood fasting
- Exclude alcohol 24 hours before
- Avoid physical activity and stress before testing
Medications:
Inform physician of anticoagulant, antiplatelet, or hormonal drug intake before testing
Prescribed for:
- Suspected blood clotting disorders
- Bleeding or thrombosis tendency
- Liver diseases
- Anticoagulant therapy monitoring (e.g., warfarin)
- Preoperative preparation
Recommended for:
- Patients with suspected hemostasis disorders
- People with cardiovascular diseases
- Pre-surgery patients
Reference values depend on laboratory methodology and are indicated on result form.
Deviations require physician consultation and comprehensive assessment.
Note: PT evaluated together with other coagulation indicators and not used as standalone diagnostic criterion.
With deviations, consultation with general practitioner, hematologist, or cardiologist is recommended.
