To determine the clotting time, venous blood is placed in a glass test tube and the time it takes to observe the blood clotting from the time of blood collection is called the clotting time. The normal range of clotting time is 4-12 minutes under normal circumstances. Prolonged clotting time is commonly associated with a deficiency of coagulation factors involved in the endogenous clotting pathway, including coagulation factor 12, coagulation factor 11, coagulation 9, 8, 10, 5, 2, and coagulation factor 1. Clotting time can also be significantly prolonged in cases where heparin or certain anticoagulant drugs are applied, and in cases of disseminated intravascular coagulation. In addition, if heparin-like substances are present in the circulation, a prolonged clotting time may also occur. A shortened clotting time is common when the blood is in a hypercoagulable state.