clotting time

time (tīm) a measure of duration. Symbol t.

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activated partial thromboplastin time  (APTT) (aPTT) (PTT) the period required for clot formation in recalcified blood plasma after contact activation and the addition of platelet substitutes; used to address the intrinsic and common pathways of coagulation.

bleeding time  the duration of bleeding after controlled, standardized puncture of the earlobe or forearm; a relatively inconsistent measure of capillary and platelet function.

circulation time  the time required for blood to flow between two given points.

clotting time , coagulation time the time required for blood to clot in a glass tube.

inertia time  the time required to overcome the inertia of a muscle after reception of a stimulus from a nerve.

one-stage prothrombin time  prothrombin t.

prothrombin time  (PT) the rate at which prothrombin is converted to thrombin in citrated blood with added calcium; used to assess the extrinsic coagulation system of the blood.

reaction time  the time elapsing between the application of a stimulus and the resulting reaction.

stimulus-response time  reaction t.

thrombin time  (TT) the time required for plasma fibrinogen to form thrombin, measured as the time for clot formation after exogenous thrombin is added to citrated plasma.

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clotting time

Etymology: AS, clott

the time required for blood to form a clot, tested by collecting 4 mL of blood in a glass tube and examining it for clot formation. The first appearance of a clot is noted and timed. The normal coagulation time in glass tubes is 5 to 15 minutes. This simple test has been used to diagnose hemophilia, but it does not detect mild coagulation disorders. Its chief application is in monitoring anticoagulant therapy. It is rarely used in clinical practice. Also called coagulation time. Compare bleeding time.

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time [tīm]

a measure of duration. See under adjectives for specific times, such as bleeding time.

activated partial thromboplastin time (APTT, aPTT) the period required for clot formation in recalcified blood plasma after contact activation and the addition of platelet substitutes such as brain cephalins or similar phospholipids; used to assess the coagulation pathways. A prolonged aPTT can indicate a deficiency of any of various coagulation factors, including factors XII, XI, IX, VIII, X, V, and II, and fibrinogen.

AEC minimal response time the shortest duration at which x-ray exposure can be terminated by automatic exposure control.

atrioventricular sequential time a fixed nonprogrammable interval that extends from the atrial stimulus to the ventricular stimulus.

bleeding time the time required for a standardized wound to stop bleeding; used as a test for platelet disorders; see also bleeding time.

circulation time the time required for blood to flow between two given points; see also circulation time.

clotting time (coagulation time) the time required for blood to clot in a glass tube; see also clotting.

cold ischemia time the time between the placement of a traumatically amputated body part in ice and the time of surgical replantation.

inertia time the time required to overcome the inertia of a muscle after reception of a stimulus.

ischemia time the total time between traumatic amputation of a limb or portion of a limb and its surgical reimplantation; it is the sum of warm and cold ischemia times.

minimal response time in radiology, the shortest possible exposure time for an x-ray film to be exposed automatically.

one-stage prothrombin time prothrombin time.

prothrombin time see prothrombin time.

real time a term used to describe a recording device that shows events simultaneously to their occurrence.

R peak time intrinsicoid deflection.

thrombin time the time required for plasma fibrinogen to form thrombin; see also thrombin time.

warm ischemia time the time interval between traumatic amputation of a limb or part and its placement on ice.

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clotting

the formation of a jellylike substance over the ends or within the walls of a blood vessel, with resultant stoppage of the blood flow. Clotting is one of the natural defense mechanisms of the body when injury occurs. A clot will usually form within 5 minutes after a blood vessel wall has been damaged. The clotting mechanism is triggered by the platelets, which disintegrate as they pass over rough places in the injured surface. As they disintegrate they release serotonin and thromboplastin. Serotonin causes constriction of the blood vessels and reduction of local blood pressure. Thromboplastin unites with calcium ions and other substances which promote the formation of fibrin. When examined under a microscope, a clot consists of a mesh of fine threads of fibrin in which are embedded erythrocytes and leukocytes, small amounts of fluid (serum), and platelets.

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clotting defects

see coagulopathy.

clotting factors

a series of plasma proteins which are related through a complex cascade of enzyme-catalyzed reactions involving the sequential cleavage of large protein molecules to produce peptides, each of which converts an inactive zymogen precursor (factor II) into an active enzyme (Iia) leading to the formation of a fibrin clot. They are designated by Roman numerals, and an additional 'a' to indicate the activated state. They are: factor I (fibrinogen), factor II (prothrombin), factor III (tissue thromboplastin), factor IV (calcium), factor V (proaccelerin), factor VI (no longer considered active in hemostasis), factor VII (proconvertin), factor VIII (antihemophilic factor), factor IX (plasma thromboplastin component; Christmas factor), factor X (stuart factor), factor XI (plasma thromboplastin antecedent), factor XII (hageman factor), factor XIII (fibrin stabilizing factor).

clotting time

the time required for blood to clot in a glass tube; a measure of the intrinsic system of coagulation. In the Lee-White method, blood in test tubes is maintained at a constant temperature and examined regularly until clotting occurs; the test can be also be performed in capillary tubes. Called also coagulation time. Less sensitive and now less often used than the activated coagulation time.

tissue clotting factor

clotting factor III; tissue thromboplastin.

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Patient discussion about clotting time.

Q. i have a small blood clot above my heart that bother me dome times. i also have had bypass sugary this past march, my heart doctor says it has nothing to do with my heart, has anyone else had this problem and if so what or how have you dealt with it?

A. laddie, my uncle had something similar (i think so anyway) but i'm not sure i understand what you mean by "above the heart" ? by uncle had a blood clot that was formed in the heart arteries and he had to a procedure and open it up. but you'll need to give me more info...