1. Living habits

Diet (such as animal liver), smoking, drinking, etc. will also affect the detection;

2. Drug Effects

(1) Warfarin: mainly affects PT and INR values;
(2) Heparin: It mainly affects APTT, which can be prolonged by 1.5 to 2.5 times (in patients treated with anticoagulant drugs, try to collect blood after the drug concentration is reduced or the drug has passed its half-life);
(3) Antibiotics: The use of large doses of antibiotics can cause the prolongation of PT and APTT. It has been reported that when the penicillin content reaches 20,000 u/ML blood, the PT and APTT can be prolonged by more than 1 times, and the INR value can also be prolonged by more than 1 times ( Cases of abnormal coagulation induced by intravenous nodoperazone-sulbactam have been reported)
(4) Thrombolytic drugs;
(5) The imported fat emulsion drugs can interfere with the test results, and high-speed centrifugation can be used to reduce the interference in the case of severe lipid blood samples;
(6) Drugs such as aspirin, dipyridamole and ticlopidine can inhibit platelet aggregation;

3. Blood collection factors:

(1) The ratio of sodium citrate anticoagulant to blood is usually 1:9, and it is mixed well. It has been reported in the literature that the increase or decrease of anticoagulant concentration has an effect on the detection of coagulation function. When the blood volume increases by 0.5 mL, the clotting time can be shortened; when the blood volume decreases by 0.5 mL, the clotting time can be prolonged;
(2) Hit the nail on the head to prevent tissue damage and the mixing of exogenous coagulation factors;
(3) The time of the cuff should not exceed 1 min. If the cuff is pressed too tightly or the time is too long, factor VIII and tissue plasmin source activator (t-pA) will be released due to ligation, and the blood injection will be too forceful. It is also the breakdown of blood cells that activates the coagulation system.

4. Time and temperature effects of specimen placement:

(1) Coagulation factors Ⅷ and Ⅴ are unstable. As the storage time increases, the storage temperature increases, and the coagulation activity gradually disappears. Therefore, the blood coagulation specimen should be sent for inspection within 1 hour after collection, and the test should be completed within 2 hours to avoid causing PT. , APTT prolongation. (2) For specimens that cannot be detected in time, the plasma should be separated and stored under a lid and refrigerated at 2 ℃ ~ 8 ℃.

5. Moderate/severe hemolysis and lipidemia specimens

Hemolyzed samples have coagulation activity similar to platelet factor III, which can shorten the TT, PT, and APTT time of hemolyzed plasma and reduce the content of FIB.

6. Others

Hypothermia, acidosis, and hypocalcemia can cause thrombin and coagulation factors to be ineffective.