What is the reason for high thromboplastin time

Elevated thromboplastin time may be caused by factors such as coagulation factor deficiency, use of anticoagulant drugs, liver disease, vitamin K deficiency, disseminated intravascular coagulation, etc.

1. Deficiency of coagulation factors:

Thromboplastin time reflects the function of exogenous coagulation pathways. When coagulation factors II, V, VII, and X are deficient, it can lead to an increase in detection values. Congenital coagulation factor deficiency, such as hemophilia B factor IX deficiency, may indirectly prolong outcomes by affecting common pathways. Acquired deficiency is common in severe bleeding and depletion of coagulation factors after large blood transfusions.

2. Effects of anticoagulant drugs:

Vitamin K antagonists such as warfarin can inhibit the synthesis of factors II, VII, IX, and X. During medication, the thromboplastin time is usually prolonged to 1.5-2.5 times the normal value. New oral anticoagulants such as rivaroxaban may also have a mild impact on test results. When using heparin therapy, attention should be paid to the false elevation caused by improper blood collection techniques.

3. Liver disease:

Cirrhotic patients may experience prolonged thromboplastin time in approximately 60% of cases due to decreased liver synthesis function and reduced production of coagulation factors. Accompanying symptoms include jaundice, ascites, and laboratory tests showing decreased albumin and abnormal transaminase levels. All coagulation factor synthesis is inhibited in acute liver failure.

4. Vitamin K deficiency:

Vitamin K is an essential cofactor for the synthesis of coagulation factors II, VII, IX, and X. insufficient intake, long-term fasting, absorption disorders, biliary obstruction, or broad-spectrum antibiotic use can all lead to deficiency. Neonatal hemorrhagic disease is a typical case, characterized by skin and mucosal bleeding occurring 2-5 days after birth.

5. Diffuse intravascular coagulation:

During DIC, a large number of microthrombi form, consuming coagulation factors, while secondary fibrinolysis occurs, manifested as prolonged prothrombin time and prothrombin time simultaneously. Laboratory features include thrombocytopenia, elevated D-dimer levels, clinically visible skin bruising, and multiple organ dysfunction.

It was found that prolonged prothrombin time needs to be comprehensively judged in conjunction with other coagulation indicators to avoid vigorous exercise and prevent collision bleeding. Diet can moderately increase green leafy vegetables rich in vitamin K, such as spinach, mustard greens, etc. Patients with cirrhosis should ensure a daily intake of 80-100g of high-quality protein, but temporary restriction is required during the onset of hepatic encephalopathy. Long term users of warfarin should maintain stable intake of vitamin K and avoid sudden and excessive consumption of foods such as natto and animal liver. It is recommended to monitor INR values weekly and adjust anticoagulation regimens based on the results.