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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.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


Farlex Partner Medical Dictionary © Farlex 2012

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.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.


Abbreviation for activated partial thromboplastin time.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
For the analysis of the aPTT, PT, and TT parameters, two sodium citrate tubes were each filled with 2 ml of blood collected from all of the dogs (n=16) before anaesthesia.
Hatta faktor XII aktivitesinin azalmis olmasina ragmen aPTT sonuclarinin normal sinirlar icerisinde olabilecegini bildiren calismalarda olmustur (17).
Presence of inhibitor is confirmed if aPTT value is greater than mean value in test tube three.
Gosterilmis koagulasyon bozuklugu (artmis protrombin zamani, artmis INR, artmis aPTT), aktif kanamanin varligi, invaziv prosedur yada cerrahi oncesi transfuzyon uzman goruslerine dayanan guncel onerilerdir (23).
Levels of Coagulation Factors and detection of FV inhibitor (64 BU) Lab test Patient's result Normal range PT 56 11-14 sec PT% 13% 90-110% INR 6.55 0.8-1.2 APTT 181 29-40 sec Fibrinogen 289 180-400 mg/dL D-Dimers 890 0-500 [micro]gr/Lt FVIII 1% 65-150 FIX 8% 65-150 FII 2% 65-150 FV 0% 65-150 FVII 1% 65-150 FX 3% 65-150 FXI 2% 65-150 FXII 3% 65-150 FVIII inhibitor 1.2 BU FV inhibitor 64 BU Lupus anticoagulant negative BU: Bethesda units; PT: prothrombin time; INR: international normalized ratio; APTT: partial thromboplastin time; FV: factor V
Parameter Survivor (n = 46) Nonsurvivor (n = 26) ALT * (U/L) 224 (127-465) 239 (108-405) [gamma]-GT * (U/L) 70 (35-227) 70 (30-279) TBIL * ([micro]mol/L) 13 (7-46) 73 (21-130) ALB (g/L) 32 (29-37) 29 (26-33) PT * (s) 13.9 (12.0-16.1) 15.4 (13.0-19.1) APTT * (s) 36.4 (29.9-42.1) 44.0 (34.9-58.0) TBA * ([micro]mol/L) 20 (8-54) 47 (32-96) INR * 1.20 (1.03-1.41) 1.28 (1.11-1.55) Parameter P ALT * (U/L) 0.862 [gamma]-GT * (U/L) 0.872 TBIL * ([micro]mol/L) 0.001 ALB (g/L) 0.152 PT * (s) 0.023 APTT * (s) 0.002 TBA * ([micro]mol/L) 0.021 INR * 0.104 ALT: alanine transaminase; [gamma]-GT: [gamma]-glutamyltransferase; TBIL: total bilirubin; ALB: albumin; PT: prothrombin time; APTT: activated partial thromboplastin time; INR: international normalized ratio; TBA: total bile acid.
An isolated aPTT prolongation suggests a deficiency or inhibitor of one or more of the intrinsic pathway clotting factors including prekallikrein, high-molecular-weight kininogen, and factors XII, XI, IX, and VIII.
Univariate analysis showed that INR, aPTT, D-D, DFR, and PLT among the laboratory variables of hemostatic assays were the risk factors for T2DM without complications (P < 0.01 for all variables, but P < 0.05 for D-D).
The PT and APTT assays were done on semiautomated photo optical coagulation analyzer (Sysmex CA-50) using reagents Thromborel S and Actin FSL, respectively.
Reagents used for testing included Siemens Thromborel[R] S for the PT/INR, Dade[R] Actin FS and CaCl2 for the APTT. Some samples (for the reference range and ERE) were aliquoted and stored frozen at-20[degrees]C until testing was performed.