Articles: partial-thromboplastin-time.
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Thrombosis research · Jan 2008
Comparative StudyUsefulness of high-concentration calcium chloride solution for correction of activated partial thromboplastin time (APTT) in patients with high-hematocrit value.
Pseudoprolongation of activated partial thromboplastin time (APTT) is a serious problem in anticoagulation therapy for patients with high hematocrit, such as cyanotic congenital heart diseases. APTT pseudoprolongation occurs when APTT assay is performed using routinely used vacuum sampling tubes containing citrate. Because the plasma fraction is small in high-hematocrit blood, the prescribed volume of citrate would be excessive for APTT assay, resulting in prolongation of clotting or APTT pseudoprolongation. CLSI--The Clinical and Laboratory Standards Institute (formerly NCCLS) method is the established method to correct the pseudoprolongation. However, the CLSI method needs repeated blood drawings and time-consuming, complicate procedures. Thus, alternative simple method is desired. ⋯ High-calcium chloride solution method is useful to correct APTT pseudoprolongation. Because of the simplicity and the need of a single blood drawing, this method would reduce the burdens of not only patients but also clinical laboratory.
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To evaluate a bench-top coagulation analyzer for determination of prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen concentration in healthy dogs. ⋯ By use of the mechanical method of analysis, fibrinogen concentrations obtained with a bench-top coagulation analyzer correlated well with results for a conventional laboratory, indicating that the coagulation analyzer is a reliable instrument for determination of this coagulation variable. Coagulation analyzer results for PT and APTT correlated less strongly with those for the conventional laboratory, but they would still be considered clinically reliable.
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Mayo Clinic proceedings · Jul 2007
ReviewHow to interpret and pursue an abnormal prothrombin time, activated partial thromboplastin time, and bleeding time in adults.
The prothrombin time (PT) and activated partial thromboplastin time (APTT) are among the most commonly ordered coagulation tests. In 2005, more than 140,000 PT and more than 95,000 APTT tests were performed at Mayo Clinic. ⋯ Abnormal results from these tests (prolonged PT, APTT, and BT), especially from tests conducted for initial evaluation of hemorrhage or for preoperative screening, may pose a diagnostic dilemma to the nonhematologist. We review the essential factors affecting test results; provide a practical approach to the evaluation of a prolonged PT, APTT, and BT; and offer suggestions on which reflexive tests are appropriate and when to consider a subspecialty consultation.
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Ann Fr Anesth Reanim · Mar 2007
Review[The abnormal activated partial thromboplastin time biphasic waveform: a red flag in the sepsis? Technique and interest as marker of the sepsis].
The biphasic waveform (BPW) is an abnormality of the optical transmission waveform obtained during measurement of the activated partial thromboplastin time on a specific photometric haemostasis autoanalyzer. This abnormality is related to calcium-dependent formation of complexes between C reactive protein and very low density lipoprotein. Biphasic waveform had a high sensitivity and negative predictive value for the identification of patients with severe sepsis and septic shock. ⋯ Further trials should be necessary using BPW for diagnostic and management procedures. Compared with other laboratory markers such as C reactive protein or procalcitonin, activated partial thromboplastin time waveform analysis is a tool that is rapid, inexpensive, effective and available 24 hours a day. When the analyzer is locally available, waveform analysis of this routine coagulation test provides information for the diagnosis of severe sepsis and the prognosis of septic patients.
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Thrombosis research · Jan 2007
Comparative Study Clinical TrialComparing the prothrombin time INR versus the APTT to evaluate the coagulopathy of acute trauma.
In trauma patients, PT/INR or aPTT cutoffs of > or =1.5x normal are often used as triggers for the transfusion of plasma. ⋯ The PT/INR and aPTT showed comparable sensitivity for single or multiple factor deficiencies in artificially deficient plasmas, but the PT/INR was more sensitive than the aPTT to low coagulation factor levels in actual trauma patients (sensitivity 84% versus 50%). The aPTT can show false positives with lupus anticoagulants and heparin contamination and false negatives in samples with elevated factor VIII. Thus, in the acute trauma setting, the PT/INR cutoff is a more reliable indicator of reduced coagulation factor levels.