Coagulation factors (Prothrombin Time) 11–12 seconds
Time it takes to produce fibrin polymers after adding thromboplastin and calcium
Increased in:
- Vitamin K deficiency and
- Impaired coagulation factor production (e.g., cirrhosis)
The liver makes many of the proteins (prothrombin & other clotting factors) needed to make blood clot. In certain liver disorders the liver cannot make enough of these proteins and so blood does not clot so well. Therefore, blood clotting tests may be used as a marker of the severity of certain liver disorders
In acute and chronic liver disease, the synthesis of prothrombin is diminished, Also in obstructive jaundice (due to vitamin K deficiency) ⇒ prolonged prothrombin Time (PT)
This may be one of the earliest abnormalities seen in hepatocellular damage, since prothrombin has a short half-life (~ 6 hours). So it must be done for every patient prone to surgery or operation.