activated partial thromboplastin time


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Related to activated partial thromboplastin time: Thrombin time, Prothrombin time, International normalized ratio

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.
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.

ac·ti·vat·ed par·tial throm·bo·plas·tin time (aPTT),

the time needed for plasma to form a fibrin clot after the addition of calcium and a phospholipid reagent; used to evaluate the intrinsic clotting system.

activated partial thromboplastin time (APTT)

activated partial thromboplastin time

A test that evaluates the clotting factors of the intrinsic pathway—except VII and XIII—by measuring the time required to form a fibrin clot. aPTT is used to screen for bleeding tendencies and to monitor heparin therapy; it is increased in coagulation factor deficiencies (factors V, VIII, IX, X, XI, XII), DIC, Hodgkin lymphoma, hypofibrinogenemia, leukaemia, cirrhosis, vitamin K deficiency, von Willebrand’s disease, and in drug therapy—e.g., heparin and aspirin.
 
Ref range
30–40 seconds.

activated partial thromboplastin time

aPTT Hematology A test that evaluates the clotting factors of the intrinsic pathway–except VII and XIII, by measuring the time required to form a fibrin clot; aPTT is used to screen for bleeding tendencies and to monitor heparin therapy; it is ↑ in coagulation factor deficiencies–factors V, VIII, IX, X, XI, XII, DIC, Hodgkin's disease, hypofibrinogenemia, leukemia, cirrhosis, vitamin K deficiency, von Willebrand's disease, and in drug therapy–eg, heparin and aspirin Ref range 30-40 secs. See Prothrombin time.

ac·ti·vat·ed par·tial throm·bo·plas·tin time

(aPTT) (ak'ti-vā-tĕd pahr'shăl throm-bō-plas'tin tīm)
The time needed for plasma to form a fibrin clot following the addition of calcium and a phospholipid reagent; used to evaluate the intrinsic clotting system.

activated partial thromboplastin time

A measurement of the time taken for the clotting system of the blood to produce the clot protein known as fibrin. The time is generally 25 to 39 seconds. This measurement is a general test of the system and is also used to assess the effectiveness of the anticoagulant drug HEPARIN. It may also be used as the basis of a test for ACTIVATED PROTEIN C RESISTANCE.

Activated partial thromboplastin time

Partial thromboplastin time test that uses activators to shorten the clotting time, making it more useful for heparin monitoring.

thromboplastin

a substance in blood and tissues which, in the presence of ionized calcium, aids in the conversion of prothrombin to thrombin. Extrinsic and intrinsic thromboplastin are formed as the result of the interaction of different clotting factors; the factors that combine to form extrinsic thromboplastin are not all derived from intravascular sources, whereas those that form intrinsic thromboplastin are.

activated partial thromboplastin time
see activated partial thromboplastin time.
extrinsic thromboplastin
the prothrombin activator formed as a result of interaction of coagulation factors III, VII, and X which, with factor IV, aids in the formation of thrombin.
thromboplastin generation time (TGT)
evaluates the first stage in blood coagulation by measuring the efficiency of prothrombinase formation.
intrinsic thromboplastin
the prothrombin activator formed as a result of interaction of coagulation factors V, VII, IX, X, XI and XII and platelet factor 3 (PF-3), which, with factor IV, aids in the conversion of prothrombin to thrombin.
plasma thromboplastin antecedent (PTA)
clotting factor XI; deficiency occurs in cattle and dogs, causing mild to severe bleeding tendencies called hemophilia C.
plasma thromboplastin component (PTC)
clotting factor IX; deficiency causes christmas disease. Called also Christmas factor, antihemophilic factor B, autoprothrombin II.
thromboplastin time
see activated partial thromboplastin time.
tissue thromboplastin
factor III, a material derived from several sources in the body (e.g. brain, lung), and is important in the formation of extrinsic prothrombin converting principle in the extrinsic pathway of blood coagulation. Called also tissue factor.
References in periodicals archive ?
In vitro neutralization of heparin in plasma prior to the activated partial thromboplastin time test: an assessment of four heparin antagonists and two anion exchange resins.
The patient had received one subcutaneous injection of low-molecular-weight heparin prophylactically and had a measured activated partial thromboplastin time of 33 seconds, a PT of 84%, and a platelet count of 151 x [10.
Interlaboratory agreement in the monitoring of unfractionated heparin using the anti-factor Xa-correlated activated partial thromboplastin time.
Three hours after presentation he had persistent vomiting and laboratory investigations suggestive of envenomation, with an associated raised activated partial thromboplastin time, international normalised ratio and decreased fibrinogen.
1,2) These findings consisted of a prolonged activated partial thromboplastin time (APTT), abnormal 1:1 mixing studies that did not correct into the normal range of the laboratory reagent/instrument combination, falsely decreased coagulation factors that corrected upon dilution, a positive dilute Russell's Viper venom assay, and a positive platelet neutralization assay.
The time elapsed until the first therapeutic activated partial thromboplastin time or heparin assay is achieved as well as time to a steady-state level will be enlightening to guide further protocol refinements.
Coagulation was assessed by two standard measurements of blood clotting time, activated clotting time (ACT) and activated partial thromboplastin time (aPTT).
In addition, the times for such global tests as the prothrombin time (PT), the activated partial thromboplastin time (APTT), the dilute Russell viper venom test (dRVVT), and the thrombin clotting time (TCT) are prolonged after NOA administration and could therefore be suitable alternatives for measuring the effect of rivaroxaban, apixaban, or dabigatran.
3) The most commonly used screening assays include the activated partial thromboplastin time and dilute Russell viper venom time.
Conventional coagulation tests such as the PT and activated partial thromboplastin time change in one direction only (i.
Adverse reactions more commonly seen in pediatric patients compared to those observed in adult patients (>10% difference) include rash, upper respiratory tract infection, prolonged activated partial thromboplastin time, and fever.
18) The activated partial thromboplastin time (APTT) was measured both in the presence and absence of exogenous APC.

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