Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Prothrombin Time”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21Linked to original sources
PubMed2001

Point-of-care prothrombin time measurement for professional and patient self-testing use. A multicenter clinical experience. Oral Anticoagulation Monitoring Study Group.

We enrolled 386 subjects in a multicenter study of a point-of-care (POC) prothrombin time (PT) testing device. POC tests were performed by health care professionals using venous and finger-stick specimens and by patients using finger-stick specimens. Venous blood also was analyzed in the local hospital laboratory and a national reference laboratory. Accurate POC results were obtained by professionals using both types of specimens. Patients' results were equivalent to those of professionals. The identification of the patient's therapeutic status based on the International Normalized Ratio (INR) was equivalent for POC and local hospital laboratory PT results; 75% of local laboratory results and 77% of POC results were within 0.4 INR of reference laboratory results, while 93% of either system (POC or local laboratory) were within 0.7 INR. Patients overwhelmingly reported satisfaction with the self-test, including the finger stick and device operation. The INR from the POC device is clinically equivalent to the laboratory INR for assessment of anticoagulation status and management decisions in professional and self-testing environments. Patients can learn to perform accurate PT testing, and POC PT testing is feasible in patients' homes.

Adolescent↗
PubMed1997

Using the international normalized ratio to standardize prothrombin time.

The international normalized ratio, or INR, was introduced in 1983 by the World Health Organization, or WHO, Committee on Biological Standards to more accurately assess patients receiving anticoagulation therapy. The INR mandates the universal standardization of prothrombin time. This article describes the method used to calculate INR, as well as its clinical relevance to the practice of dentistry.

Anticoagulants↗
PubMed1993

Prothrombin time and partial thromboplastin time as a predictor of bleeding in patients with dengue hemorrhagic fever.

Eighty-nine pediatric patients admitted at the University of Santo Tomas Hospital from June to December 1992, with the clinical diagnosis of dengue hemorrhagic fever (DHF) were studied with the following objectives: To determine the possible use of hematocrit, platelet count, prothrombin time (PT) and partial thromboplastin time (PTT) as predictors of bleeding and outcome in patient with DHF. The following were established: PTT can be an index in predicting bleeding in DHF. The tendency to bleed is greater with prolongation of > 30 seconds; platelet count can be a predictor of mortality, with death six times greater among those platelet count < 50,000/microliters than those whose platelet count was > 50,000/microliters. PT can also predict bleeding in patients with DHF.

Adolescent↗
PubMed2006

Quality assessment of CoaguChek point-of-care prothrombin time monitors: comparison of the European community-approved procedure and conventional external quality assessment.

BACKGROUND: There is a need for dependable quality assessment (QA) of the widely used CoaguChek point-of-care testing prothrombin time monitor. By use of the prescribed set of 5 CoaguChek certified international normalized ratio (INR) QA plasmas, we compared the reliability of the immediate QA of individual monitors described in the European Community-recommended Technology Implementation Plan with conventional external QA analysis. METHODS: Experienced staff tested CoaguChek point-of-care monitors in routine use for controlling oral anticoagulant dosage at 9 Netherlands Thrombosis Service Centres. Testing was performed with both the certified CoaguChek INR for a set of 5 QA individual plasmas from the Eur Con Action on Anticoag (ECAA) and conventional external QA analysis. RESULTS: Patients brought 523 CoaguChek monitors to our service centers for assessment. The proportion with unsatisfactory performance indicated by a 15% deviation from the ECAA set was compared with 15% deviation from overall median INR of all CoaguChek monitors in the survey, as in conventional QA analysis. The results were similar (20.3% and 18.5%, respectively). Interlot differences of CoaguChek test strips were detected, but the incidence of unsatisfactory performance was similar with both analyses, from 6.5% to 37.5% with the certified INR method and from 5.9% to 33.3% with the overall median analysis. CONCLUSIONS: The results validate the use of the European Action on Anticoagulation rapid single-instrument QA-specific procedure for CoaguChek users compared with the nonspecific conventional QA analysis that relies on deviation from the overall median INR.

Administration, Oral↗
PubMed1999

Correction of both prothrombin time and primary haemostasis by recombinant factor VII during therapeutic alcohol injection of hepatocellular cancer in liver cirrhosis.

We evaluated the efficacy of recombinant factor VII to correct impaired haemostasis in a patient with liver cirrhosis requiring an invasive procedure. A test intravenous bolus of 80 microg/kg of recombinant factor VII was given to a Jehovah's Witness, with a solitary 4.4-cm hepatocellular carcinoma and underlying hepatitis C virus cirrhosis, in an attempt to correct his haemostatic disorders and safely inject the tumour with alcohol. An extensive portal block had precluded consideration of liver transplantation. Haemostasis was evaluated by clotting assays, bleeding time and thromboelastography 10 min before and 10 min and 1, 2, 4, 8 and 24 h after factor VII infusion. Parameters of both coagulation (prothrombin time) and platelet function (bleeding time and the alpha and ma parameters of thrombelastography) were improved 10 min after factor VII infusion; improvements lasted 4 to 8 h or more. Platelet count did not change and there was no evidence of disseminated intravascular coagulation. The improvements in haemostatic parameters correlated significantly with the increases in factor VII plasma concentrations (p<0.04). Factor VII clearance was 25.1 U/h/kg and its half-life was 5.8 h. The same dose of recombinant factor VII was given to the patient 1 week later, just before the alcohol injections. The patient had no subsequent bleeding or other complication, with no change in haemoglobin levels over 24 h. Thus, recombinant factor VII represents a therapeutic advance, as it can correct fully both coagulation and platelet function defects in cirrhosis and allow invasive procedures to be performed safely.

Carcinoma, Hepatocellular↗
PubMed2004

Prothrombin time international normalized ratio monitoring by self-testing.

PURPOSE OF REVIEW: The increasing numbers of patients on oral anticoagulants may challenge the traditional organization of patient monitoring. The availability of portable coagulometers capable of measuring prothrombin time (PT) international normalized ratio (INR) in a drop of capillary blood facilitates decentralization of monitoring by self-testing. This article reviews the literature on use of portable coagulometers. RECENT FINDINGS: Numerous studies have evaluated the reliability of portable coagulometers in testing the PT-INR. This has been assessed by statistically as well as clinically relevant criteria. Other studies have been devoted to developing calibration models fulfilling the criteria recommended by the World Health Organization (WHO) for the calibration of INR measuring systems. Finally, studies have assessed the value of schemes for patient training and for the long-term quality assurance of portable coagulometers. SUMMARY: It can be concluded from the published studies that PT-INR self-testing may be considered as a suitable alternative to conventional laboratory testing. For the PT-INR to be reliable, manufacturers of portable coagulometers should calibrate their devices against international standards for thromboplastin with procedures similar to those recommended by WHO for conventional measuring systems. Training of patients and implementation of appropriate quality assessment schemes are also essential prerequisites for the success of PT-INR self-testing.

Administration, Oral↗
PubMed1996

Effect of a reduced vitamin K supplementation on prothrombin time in prematures and high-risk neonates.

Recommendations for vitamin K supplementation were recently changed to 3 x 1 mg orally in healthy term neonates and 0.2 mg parenterally in prematures and high-risk neonates. Prothrombin times (PT) at reduced vitamin K doses (120 patients, 170 samples) during the first 6 weeks of life were below 40% in 6 patients only; all low PTs were unrelated to vitamin K. In the remaining patients, median PT was 100%; 79% of patients had values above 70%. PT was related to birthweight, gestational age and age. There was no decrease over the observation period. Following reduced oral and parenteral vitamin K regimens PTs were well within published reference values for neonates given larger amounts of vitamin K.

Administration, Oral↗
PubMed1989

Comparison of two automated coagulometers and the manual tilt-tube method for the determination of prothrombin time.

Two automatic coagulometers--ACL 810 (Instrumentation Laboratory), a laser-nephelometric centrifugal analyzer, and KoaguLab 40 A (Ortho Diagnostics), an optical automatic coagulometer--were compared with the manual tilt-tube method for the performance of prothrombin time (PT). Seven ISI- (International Sensitivity Index) calibrated commercial thromboplastin reagents were used for duplicate determinations in 30 normal subjects, 30 patients with liver disease, and 30 patients receiving stabilized oral anticoagulation. Clotting times were longer with the manual method than with ACL 810 and, to a lesser extent, with KoaguLab 40 A. Average imprecision of duplicate determinations (CV) was less than 1% with ACL 810; KoaguLab 40 A and the manual method had similarly higher imprecisions (2.8% and 2.7%). Differences in origin and slope of the regression curves of clotting times obtained with the coagulometers over the tilt-tube method were observed with all the reagents tested. Transformation of clotting times to PT ratios did not eliminate the bias resulting from the different clot-detection methods. A higher percentage of patients with liver disease had abnormal PT ratios when their plasma was tested with the coagulometers than with the manual method. Transformation of PT ratios to International Normalized Ratios effectively eliminated the bias resulting from the different thromboplastin reagents but had no effect on the bias resulting from the different clot-detection methods. A significant proportion of patients appeared excessively anticoagulated (INR greater than 4.5) with the coagulometers but not with the manual method. These results highlight the need for standardization of both instrumentations and reagents to improve monitoring of oral anticoagulant treatment.

Anticoagulants↗
PubMed1989

Patient self-management of oral anticoagulation guided by capillary (fingerstick) whole blood prothrombin times.

Physician management of long-term oral anticoagulation is labor-intensive and costly. Moreover, errors of communication may lead to complications. We assessed the ability of patients to regulate their own therapy based on fingerstick prothrombin times (PTs) in order to avoid these problems. Such management was made possible by the availability of a device capable of measuring a PT from a capillary sample of whole blood. Sixteen patients adjusted their warfarin therapy based on specially developed guidelines for a mean duration of 43 weeks (range, 8 to 92 weeks). Four hundred fifty-eight PTs were measured by patients at home during the entire study. Three hundred ninety-three were in therapeutic range and patients correctly continued their dosages. Of the 65 nontherapeutic PTs, patients made correct dose adjustments in 49 and incorrect adjustments in 16. These incorrect adjustments were minor and judged to be clinically insignificant. They often resulted from a misunderstanding of the dosage guidelines. Given the slow onset of warfarin's effect, the assessment of the PT on a weekly or biweekly basis, and the ability to refine dosage guidelines, these errors were not felt to represent a serious drawback to the concept of warfarin self-management. No complications of therapy occurred during the study. Although this mode of therapy needs further evaluation, this pilot study suggests that patient self-management is feasible and that this model of anticoagulant care offers the potential for improved care at reduced cost.

Administration, Oral↗
PubMed2006

Prolongation of the prothrombin time and activated partial thromboplastin time in children with sickle cell disease.

BACKGROUND: Patients with sickle cell disease (SCD) have high rates of perioperative complications, including bleeding 1,2. PROCEDURES: We conducted a retrospective review of pre-operative coagulation studies in pediatric patients with SCD followed by a prospective study of 100 well children with SCD to determine the prevalence of abnormal coagulation screening tests, and to evaluate potential etiologies. RESULTS: In the retrospective study, 32/84 (38.1%) had a prolonged prothrombin time (PT), compared to 8/100 in the prospective study. Prolongations of the activated partial thromboplastin time (aPTT) were less common. Children in the prospective study with prolonged PTs had significantly lower levels of Factor V and VII compared to those with normal PTs. Factor VII levels were <50% in 4/8 with long PTs, compared to 3/92 with normal PTs, P=0.001. Though retrospectively, several patients had normalization of their PT with vitamin K, there was no laboratory evidence of vitamin K deficiency in the prospective study. In the retrospective analysis, six of seven children who had pre-operative coagulation studies and significant intraoperative blood loss had prolonged PTs (P=0.04). CONCLUSIONS: Children with SCD admitted for surgical procedures were more likely to have prolonged PTs than those tested at a well visit. There was intra-patient variability in coagulation studies that may be related to clinical status, hepatocellular dysfunction, and/or increased clotting factor consumption. Future well-designed prospective studies to determine whether abnormal coagulation studies are associated with an increased risk of perioperative bleeding in children with SCD are necessary.

Adolescent↗
PubMedDate not supplied

Self-management of oral anticoagulants with a whole blood prothrombin-time monitor in elderly patients with atrial fibrillation.

The efficacy of oral anticoagulants (OAC) in reducing the incidence of stroke in elderly patients with atrial fibrillation (AF) has been well documented. The intensity of OAC therapy and deviations in the prothrombin time (PT) are the strongest risk factor for bleeding complications in elderly patients. The aim of this study was to evaluate a more rigorous regulation of OAC by the use of a portable whole blood PT-monitor (CoaguChek) in elderly patients with AF (age 65-80 years). The study group consisted of 20 patients, of whom 17 were evaluable, which were trained to use to CoaguChek monitor and adjust their anticoagulant dose for 12 months. The control group, 20 patients matched for age, gender and the duration of OAC treatment, were tested in an anticoagulant clinic and their OAC dose was adjusted by a physician. To validate the PT-monitor results, the patients performed a total of 129 simultaneous venous blood PT tests at various time points. The correlation coefficient R(2) was 0.707 indicating the accuracy of the CoaguChek results. The self-managed patients perform more frequent measurements 46 +/- 8.9 vs. 15.7 +/- 3.1 PT tests per patient. They demonstrated a within the therapeutic range INR in 80.5% of the tests (95% confidence interval, 76.5-84.1%) as compared to 72.4% (95% confidence interval, 68.5-76.5%) in the control group (p = 0.057). The median value for all CoaguChek International Normalized Ratio (INR) recordings was within therapeutic range in the self-management group as well as in the control group. There were fewer INR results below or above the therapeutic range in the study group. None of the patients had hemorrhagic or thrombotic events during the study. Overall, the study group expressed high satisfaction from using the home monitor. We conclude that home PT monitoring and self-management of OAC are feasible in a motivated population of elderly patients with atrial fibrillation and are probably cost effective.

Administration, Oral↗
PubMed2000

Evaluation of solvent/detergent-treated plasma in patients with a prolonged prothrombin time.

OBJECTIVES: To compare the laboratory and clinical outcome of patients who received solvent/detergent-treated plasma (SDP) and fresh-frozen plasma (FFP). METHODS: A randomized, double-blinded study to assess the ability of SDP and FFP to reduce a prolonged prothrombin time (PT) to </=15 s in patients with acquired coagulation deficits. RESULTS: 45 patients (22 SDP vs. 23 FFP) were treated with 71 infusions. There were no significant differences in mean dose of plasma infused (7.8 ml/kg for SDP vs. 8.0 ml/kg for FFP, p = 0.46), percentage of patients who corrected their PT to </=15 s (32% for SDP vs. 26% for FFP, p = 0.67), or percentage of patients whose bleeding ceased (27% for SDP vs. 22% for FFP). CONCLUSION: No clinical or statistically significant differences were observed after infusion with SDP or FFP in patients with acquired coagulation deficits.

Adult↗