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At least 19 recordsLinked to original sources
PubMed1989

[Laboratory controls of heparin therapy with thrombin time, partial thromboplastin time and activated recalcification time].

For the laboratory control of a heparin therapy thrombin time, partial thromboplastin time and activated recalcification time are used. On account of distinct differences in the heparin sensitivity of these reactions an indication-related application is necessary. The ability of evidence and the possibility of establishing test-specific therapeutic regions are restricted by differences caused by reagents, individual variability and influence by accompanying haemostasiological changes. The own approach, taking into consideration the so-called heparin resistance, it presented.

Blood Coagulation Tests↗
PubMed2002

The determinants of activated partial thromboplastin time, relation of activated partial thromboplastin time to clinical outcomes, and optimal dosing regimens for heparin treated patients with acute coronary syndromes: a review of GUSTO-IIb.

CONTEXT: Unfractionated heparin remains widely utilized in the treatment of acute coronary syndromes (ACS). However, limited data exist on optimal dosing and range of activated partial thromboplastin time (aPTT) in this setting. A large trial of thrombolysis for acute myocardial infarction has reported an association between longer aPTTs and adverse outcomes. OBJECTIVES: Estimate the optimal heparin-dosing regimen in achieving early therapeutic aPTTs (50 to 75 seconds) and determine the association of aPTT and death, reinfarction, and bleeding in population with ACS. DESIGN: Subgroup analysis within a randomized, controlled trial of 5861 patients given unfractionated heparin who had aPTTs at 6, 12, or 24 hours, with outcome analyses by weight categories. SETTING: In 373 hospitals in 13 countries from May 1994 to October 1995. PATIENTS: A total of 12142 patients admitted for ACS, stratified by the presence (n = 4131) or absence (n = 8011) of ST-segment elevation, and randomized to 72 hours of unfractionated heparin. RESULTS: In a simulated weight-adjusted model, based on retrospective grouping by weight, a simulated dose of 60-U/kg bolus and 12-U/kg/h infusion resulted in the highest proportion of therapeutic aPTTs. After adjustment for baseline variables, longer 12-hour aPTT was associated with the composite of 30-day death or reinfarction in patients not treated with thrombolytic therapy (odds ratio, 1.10; 95% CI, 1.00 to 1.22; P = 0.047). Longer aPTT at 6 hours was associated with increased moderate or severe bleeding for the entire cohort. There was also a significant, nonlinear correlation of the 12-hour aPTT with moderate or severe bleeding in thrombolysis-treated patients. CONCLUSIONS: For ACS patients who are treated with heparin, aPTT is highly associated with body weight. Longer aPTT within the first 12 hours is associated with adverse outcomes in ACS. Heparin dosing for ACS should be weight based.

Acute Disease↗
PubMed1992

Evaluation of prothrombin time and partial thromboplastin time.

Prothrombin time (PT) and partial thromboplastin time (PTT) tests are commonly ordered for hospitalized patients. A significant reduction in laboratory workload and expense can be achieved if these tests are ordered appropriately. The likelihood that the patient will benefit from these tests is small.

American Medical Association↗
PubMed1988

Effects of reagent and instrument on prothrombin times, activated partial thromboplastin times and patient/control ratios.

Activated partial thromboplastin times accumulated from two proficiency testing surveys were analyzed to determine simultaneously the effects of the method and reagent used. Prothrombin time results were reevaluated concomitantly for comparison. A robust two-way analysis of variance was applied to determine the effect of method and reagent on APTT results. The effect of the reagent and method on the ratio of abnormal to normal plasma clotting times was determined. We found a substantial difference in ratios for the PT using different reagents on the same instrument. There was an even larger effect of reagents on APTT ratios. Our finding of substantial reagent effects for the PT and APTT clearly support the need for standardization. We found standardization to be feasible only for the PT, and only if applied in a form consistent with the inherent error structure of the data. For the APTT, the present methodology and plasma samples did not achieve consistent standardization.

Blood Coagulation Tests↗
PubMed2005

Preoperative screening for coagulopathy using prothrombin time and partial thromboplastin time in patients requiring primary cranial vault remodeling.

BACKGROUND: The aim of this study was to investigate the prevalence of abnormal preoperative screening prothrombin time and partial thromboplastin time in patients listed for primary cranial vault remodeling that required hematologic workup and their diagnoses and subsequent management. METHODS: This retrospective analysis was performed from January of 2000 to December of 2003 at the International Craniofacial Institute, Dallas, Texas, on a total of 168 patients. RESULTS: All patients had a normal prothrombin time. Abnormally raised partial thromboplastin time was found in six patients (prevalence of 3.57 percent), one who had factor XI deficiency, one who had a borderline factor XI deficiency and circulating inhibitor, one who had an intermittent factor XI deficiency and circulating inhibitor, one who had a borderline von Willebrand's disease with low factor XII, and the remaining two who had a circulating inhibitor of coagulation. Of these six patients, the perioperative management was altered in four of five patients, and one patient declined surgery out of fear of surgical morbidity. The surgery of one patient was aborted intraoperatively because of abnormal bleeding without clot formation after the calvarial burr holes had been drilled. The mean blood loss was 183 ml for the four patients with completed surgery and 100 ml for one patient. CONCLUSIONS: The authors conclude that even though the prevalence of abnormal screening partial thromboplastin time in these patients was low (3.57 percent), detection of an abnormal result required preoperative correction of coagulopathy in 80 percent of cases.

Blood Coagulation Disorders↗
PubMed1980

Monitoring of heparin treatment. Comparison of thrombin time, activated partial thromboplastin time, and plasma heparin concentration, and analysis of the behavior of antithrombin III.

Three laboratory methods for monitoring heparin treatment have been compared using 63 plasma samples: the thrombin time, the activated partial thromboplastin time, and the measurement of the heparin concentration using a chromogenic substrate. A good correlation was found between the methods. However, the intensity of anticoagulation was identical in only 27 of the 63 samples (43%) when the thrombin time and the activated partial thromboplastin time were compared. Fully discordant results were recorded for four samples (6%). The thrombin time was found to be more closely related to the plasma heparin concentration than was the activated partial thromboplastin time. Both antithrombin-III activity and immunologic levels were lower in the group with strong heparinization. It is suggested that the thrombin time is a good and safe method for monitoring heparin treatment.

Antithrombin III↗
PubMedDate not supplied

Influence of fibrinogen degradation products on thrombin time, activated partial thromboplastin time and prothrombin time of canine plasma.

To investigate how thrombin time, activated partial thromboplastin time (APTT) and prothrombin time are influenced by fibrinogen degradation products (FDP), different concentrations (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8 and 1.0 mg/ml) of the purified FDP X, Y, D and E were added to the plasma of healthy dogs. If fragment Y was added to the plasma a considerable inhibitory effect could be demonstrated for all three test systems. A significant prolongation (p < 0.05) was found for concentrations of > or =0.1 mg/ml (thrombin time, APTT) and > or =0.2 mg/ml (prothrombin time). With FDP Y concentrations from >0.185 mg/ml (prothrombin time) to >0.24 mg/ml (APTT) coagulation time was prolonged beyond the respective reference range. As regards the other fragments, a comparable inhibitory effect could only be shown for fragment X added to the thrombin time test system. This effect can most probably be explained by the competition of the FDP X and fibrinogen for the fibrinogen binding sites of thrombin, rather than by a fibrin polymerization disorder. The results demonstrate that for plasma with normal fibrinogen concentration the group tests are only prolonged beyond the reference range at FDP concentrations very rarely found in spontaneous hyperfibrinolysis.

Animals↗
PubMed2001

Evaluation of a point-of-care coagulation analyzer for measurement of prothrombin time, activated partial thromboplastin time, and activated clotting time in dogs.

OBJECTIVE: To evaluate a point-of-care coagulation analyzer (PCCA) in dogs with coagulopathies and healthy dogs. ANIMALS: 27 healthy and 32 diseased dogs with and without evidence of bleeding. PROCEDURE: Prothrombin time (PT), activated partial thromboplastin time (aPTT), and activated clotting time (ACT) were determined, using a PCCA and standard methods. RESULTS: Using the PCCA, mean (+/- SD) PT of citrated whole blood (CWB) from healthy dogs was 14.5+/-1.2 seconds, whereas PT of nonanticoagulated whole blood (NAWB) was 10.4+/-0.5 seconds. Activated partial thromboplastin time using CWB was 86.4+/-6.9 seconds, whereas aPTT was 71.2+/-6.7 seconds using NAWB. Reference ranges for PT and aPTT using CWB were 12.2 to 16.8 seconds and 72.5 to 100.3 seconds, respectively. Activated clotting time in NAWB was 71+/-11.8 seconds. Agreement with standard PT and aPTT methods using citrated plasma was good (overall agreement was 93% for PT and 87.5% for aPTT in CWB). Comparing CWB by the PCCA and conventional coagulation methods using citrated plasma, sensitivity and specificity were 85.7 and 95.5% for PT and 100 and 82.9% for aPTT, respectively. Overall agreement between the PCCA using NAWB and the clinical laboratory was 73% for PT and 88% for aPTT. Using NAWB for the PCCA and citrated plasma for conventional methods, sensitivity and specificity was 85.7 and 68.4% for PT and 86.7 and 88.9% for aPTT, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: The PCCA detected intrinsic, extrinsic, and common pathway abnormalities in a similar fashion to clinical laboratory tests.

Animals↗