Does international normalized ratio level predict pulmonary embolism?

BACKGROUND: Preventing pulmonary embolism is a priority after major musculoskeletal surgery. The literature contains discrepant data regarding the influence of anticoagulation on the incidence of pulmonary embolism after joint arthroplasty. The American College of Chest Physicians guidelines recommend administration of oral anticoagulants (warfarin), aiming for an international normalized ratio (INR) level between 2 and 3. However, recent studies show aggressive anticoagulation (INR \u3e 2) can lead to hematoma formation and increased risk of subsequent infection. QUESTIONS/PURPOSES: We asked whether an INR greater than 2 protects against pulmonary embolism. PATIENTS AND METHODS: We identified 9112 patients with 10,122 admissions for joint arthroplasty between 2004 and 2008. All patients received warfarin for prophylaxis, aiming for an INR level of 2 or lower. We assessed 609 of 10,122 admissions (6%) for pulmonary embolism using CT, ventilation/perfusion scan, or pulmonary angiography, and 163 of 10,122 admissions (1.6%) had a proven pulmonary embolism. RESULTS: Fifteen of 163 admissions (9%) had an INR greater than 2 before or on the day of workup compared to 35 of 446 admissions (8%) who were negative. We observed no difference between the INR values in patients with or without pulmonary embolism. CONCLUSIONS: We found no clinically relevant difference in the INR values of patients who did or did not develop pulmonary embolism. The risk of bleeding should be weighed against the risk of pulmonary embolism when determining an appropriate target INR for each patient, as an INR less than 2 may reduce the risk of bleeding while still protecting against pulmonary embolism. LEVEL OF EVIDENCE: Level III, therapeutic study. See Instructions to Authors for a complete description of levels of evidence

Optimal intensity of oral anticoagulant therapy after myocardial infarction

AbstractObjectives.This study attempted to determine the optimal intensity of anticoagulant therapy in patients after myocardial infarction.Background.Treatment with oral anticoagulant therapy entails a delicate balance between over- (risk of bleeding) and under-anticoagulant (risk of thromboemboli). The optimal intensity required to prevent the occurrence of either event (bleeding or thromboembolic) is not known.Methods.A method was used to determine the optimal intensity of anticoagulant therapy by calculating incidence rates for either event associated with a specific international normalized ratio. The numerator included events occurring at given international normalized ratios, and the denominator comprised the total observation time.Results.The study population included 3,404 myocardial infarction patients enrolled in the ASPECT (anticoagulants in the Secondary Prevention of Events in Coronary Thrombosis) trial. Total treatment was 6,918 patient-years. Major bleeding occurred in 57 patients (0.8/100 patient-years), and thromboembolic complications in 397 (5.7/100 patient-years). The incidence of the combined outcome (bleeding or thromboembolic complications) with international normalized ratio < 2 was 8.0/100 patient-years (283 events in 3,559 patient-years), with international normalized ratios between 2 and 3, 3.9/100 patient-years (33 events in 838 patient-years); 3.2/100 patient-years (57 events in 1,775 patient-years) for international normalized ratios between 3 and 4; 6.6/100 patient-years (37 events in 564 patient-years) for international normalized ratios between 4 and 5; and 7.7/100 patient-years (14 events in 182 patient-years) for international normalized ratios >5. After adjustment for achieved international normalized ratio levels, significant predictors were higher levels of systolic blood pressure and age.Conclusions.If equal weight is given to hemorrhagic and thromboembolic complications, these results suggest that the optimal intensity of long-term anticoagulant therapy for myocardial infarction patients lies between 2.0 and 4.0 international normalized ratio, with a trend to suggest an optimal intensity of 3.0 to 4.0

Standardization of Prothrombin Time/International Normalized Ratio (PT/INR)

The prothrombin time (PT) represents the most commonly used coagulation test in clinical laboratories. The PT is mathematically converted to the international normalized ratio (INR) for use in monitoring anticoagulant therapy with vitamin K antagonists such as warfarin in order to provide test results that are adjusted for thromboplastin and instrument used. The INR is created using two major PT �correction factors�, namely the mean normal PT (MNPT) and the international sensitivity index (ISI). Manufacturers of reagents and coagulometers have made some efforts to harmonizing INRs, for example, by tailoring reagents to specific coagulometers and provide associated ISI values. Thus, two types of ISIs may be generated, with one being a �general� or �generic� ISI and others being reagent/coagulometer-specific ISI values. Although these play a crucial role in improving INR results between laboratories, these laboratories reported INR values are known to still differ, even when laboratories use the same thromboplastin reagent and coagulometer. Moreover, ISI values for a specific thromboplastin can vary among different models of coagulometers from a manufacturer using the same method for clot identification. All these factors can be sources of error for INR reporting, which in turn can significantly affect patient management. In this narrative review, we provide some guidance to appropriate ISI verification/validation, which may help decrease the variability in cross laboratory reporting of INRs. © 2020 John Wiley & Sons Lt

Does routine repeat testing of critical laboratory values improve their accuracy?

Background: Routine repeat testing of critical laboratory values is very common these days to increase their accuracy and to avoid reporting false or infeasible results. We figure that repeat testing of critical laboratory values has any benefits or not. Methods: We examined 2233 repeated critical laboratory values in 13 different hematology and chemistry tests including: hemoglobin, white blood cell, platelet, international normalized ratio, partial thromboplastin time, glucose, potassium, sodium, phosphorus, magnesium, calcium, total bilirubin and direct bilirubin. The absolute difference and the percentage of change between the two tests for each critical value were calculated and then compared with the College of American Pathologists/Clinical Laboratory Improvement Amendments allowable error. Results: Repeat testing yielded results that were within the allowable error on 2213 of 2233 specimens (99.1). There was only one outlier (0.2) in the white blood cell test category, 9 (2.9) in the platelet test category, 5 (4) in the partial thromboplastin time test category, 5 (4.8) in the international normalized ratio test category and none in other test categories. Conclusion: Routine, repeat testing of critical hemoglobin, white blood cell, platelet, international normalized ratio, partial thromboplastin time, glucose, potassium, sodium, phosphorus, magnesium, calcium, total bilirubin and direct bilirubin results does not have any benefits to increase their accuracy

Experimental studies of QCD using flavour tagged jets with DELPHI

Identified $b\overline{b}g$ and $q\overline{q}\gamma$ events from DELPHI are used to measure the ratio of the mean charged particle multiplicity distribution between gluon and quark jets. The dependence of this ratio with the jet energy is established using about three million Z$^0$ decays. Results from all other detectors are discussed and compared. A nice agreement is found among all them. The ratio between the normalized total three-jet cross sections of $b\overline{b}g$ and $q\overline{q}g, q \equiv u,d,s$ events is also determined. The preliminary value obtained indicates that $b$ quarks are experimentaly seen to radiate less than light quarks due to their higher mass. The suggested experimental error is $\sim$300 MeV for the $b$ mass determination at the M$_Z$ scale.Comment: Latex, 5 pages, 3 figures,to appear in the Proceedings of the High Energy Physics International Euroconference on Quantum Chromodynamics (QCD '96), Montpellier, France, 4-12th July 1996. Ed. S. Narison, Nucl Phys. B (Proc. Suppl.

International Normalized Ratio (INR): Performance of External Quality Assessment 2016 results - PNAEQ and ECAT Foundation

The International Normalized Ration (INR) is derived from the measurement of the Prothrombin Time (PT) and the International Sensitivity Index (ISI), and is a quantitative measure of the responsiveness of individual thromboplastin reagents to the different clotting factors involved in the PT measurement. Under the INR system, all results are standardized. For example, a person taking an oral anticoagulant (ex. Coumadin) would need regularly to have a blood test to measure the INR. The INR permits patients on anticoagulants to travel and obtain comparable test results wherever they are. So it is very important to verify the laboratories performance over this test. In 2014 the Portuguese National External Quality Assessment Program (PNAEQ) has established a consortium with ECAT Foundation for INR measurement where Portuguese laboratories are included in the statistical analysis. The main objective of this study was to evaluate the performance for INR of PNAEQ participants that used two different thromboplastin reagents during 2016 and compared those with the results of ECAT participants.N/

PROFIL NILAI INTERNATIONAL NORMALIZED RASIO (INR) PADA PASIEN STROKE ISKEMIK DI RUMAH SAKIT UMUM DAERAH DR. ZAINOEL ABIDIN (RSUDZA) BANDA ACEH

ABSTRAKStroke merupakan kematian jaringan otak yang bersifat irevesibel oleh kerusakan, penyumbatan, atau perdarahan otak. Salah satu penyebab stroke adalah gangguan hemostatis seperti kelainan koagulasi pembuluh darah. Kelainan koagulasi darah dapat diukur dengan menggunakan International Normalized Ratio/INR. Tujuan penelitian ini adalah untuk mengetahui profil nilai INR pada stroke iskemik di RSUD Zainoel Abidin Banda Aceh dengan menggunakan data sekunder yaitu rekam medik dan hasil laboratorium pada bulan Oktober-Desember 2016. Penelitian ini merupakan penelitian deskriptif. Pengambilan sampel dilakukan dengan retrospektif teknik consecutive sampling selama 1 tahun, populasi dari 476 pasien didapatkan 41 responden yang memenuhi kriteria inklusi.Hasil penelitian ini didapatkan nilai rerata INR pada laki-laki 2.3191 detik dan perempuan 1,1979 detik. Nilai rerata INR berdasarkan usia adalah kurang dari 55 tahun 2,0793 detik, usia 55-65 detik tahun 1,2655 detik dan usia lebih dari 65 tahun 1,9113 detik. Kata kunci: Stroke, koagulasi darah, International Normalized Ratio/INRABSTRACTStroke is the death of brain tissue which is irreversible toward the demage, stoppage, or cerebral hemorrhage. One cause of stroke is a hemostatic disorder such as blood vessels coagulation disorder. Blood vessels coagulatiom disorder can be measured by using International Normalized Ratio/INR. The objective of this research was to find out the INR score profile on ischemic stroke at RSUD Zainoel Abidin Banda Aceh by using secunder data namely medical record and laboratory result on October-December 2016. This research was a descriptive research. Sampling process was conducted by using retrospective consecutive sampling technique for a year, population from 476 pasient there was obtained 41 respondents who fulfilled the inclution requirement. From the result of this research, obtained the average score of INR on man is 2.3191 seconds and woman is 1,1979 seconds. The average score of INR based on age is that less than 55 years old is 2,0793 seconds, 55-65 years of age is 1,2655 seconds and up to 65 years of age is 1,9113 seconds.Keywords: Stroke, blood coagulation, International Normalized Ratio/ IN