Japanese
Titleプロトロンビン時間測定におけるISI/INRシステムの問題点:同一検体4施設同時測定による検討
Subtitle原著
Authors上塚芳郎*, 櫻川信男**, 和田英夫***, 相沢義房****, 小沢哲夫**, 青崎正彦*****, 大木勝義*, 井上美幸******, 笠貫宏*
Authors(kana)
Organization*東京女子医科大学循環器内科, **富山医科薬科大学臨床検査医学, ***三重大学第2内科, ****新潟大学第1内科, *****国立横浜病院, ******東京女子医科大学中央検査部
Journal循環制御
Volume21
Number3
Page271-277
Year/Month2000/
Article原著
Publisher日本循環制御医学会
Abstract1984年, ICTH(International Committee on Thrombosis and Haemostasis)現SSC(Scientific and Standardization Committee)は抗凝固療法のモニタリング法としてプロトロンビン時間(PT)による場合はINR表示を用いることを推奨したが, わが国ではいまだにトロンボテスト(TT)を用いている施設が多いのが現状である. 一方, わが国においては欧米におけるよりもより緩やかな凝固能のコントロールでも血栓症の発現が少ないとの報告もあり, わが国におけるPT-INRの治療域設定の必要性が言われている. 全国的にPT-INR表示を普及するにあたっての問題点を洗い出すために第一段階の検討として以下の研究を行った. 東京女子医科大学において採血したワーファリン療法中の7症例の血漿を3施設に送付し, 同時に4施設において測定し, INR表示を用いて比較検討した. 本来PT-INRに換算すれば, たとえ異った試薬, 異った測定機器を使用して測定してもほぼ一致した値になることが予測されたが, 一部の施設間では測定値に有意差を認めた. すなわち施設1と施設3は同じシンプラスチンオート試薬を用いていたのにもかかわらず, かえって秒数よりもINRで差異が認められた. 原因としてINRの計算に必要な健常者のPTの設定と測定機器の違いからくる差異に問題があったと推定された. 今後INR表示を普及するに際しては正常者対照例の設定と機器の違いからくる差異にも注意が必要と考えられた.
Practice基礎医学・関連科学
KeywordsProthrombin time, Thrombotest, INR, ISI, Anticoagulany.
English
TitleSome Concern about ISI/INR System: Experience from Simultaneous Measurement of the Same Plasma at 4 Different Laboratories
Subtitle
AuthorsYoshio Uetsuka*, Nobuo Sakuragawa**, Hideo Wada***, Yoshifusa Aizawa****, Tetsuo Ozawa**, Masahiko Aosaki*****, Katsuyoshi Ooki*, Miyuki Inoue******, Hiroshi Kasanuki*
Authors(kana)
Organization*Department of Cardiology,Tokyo Women's Medical University, **Department of Clinical Laboratory Medicine,Toyama Medical and Pharmaceutical University, ***Second Department of Internal Medicine,Mie University,School of Medicine, ****First Department of Internal Medicine,Niigata University,School of Medicine, *****Yokohama National Hospital, ******Central Clinical Laboratories,Tokyo Women's Medical University
JournalCirculation Control
Volume21
Number3
Page271-277
Year/Month2000/
ArticleOriginal article
PublisherJapan Society of Circulation Control
AbstractIn 1984, the Scientific and Standardization Committee (formerly ICTH) recommended the use of International Sensitivity Index and International Normalized Ratio (ISI/INR) System for the monitoring of oral anticoagulant therapy. This system is introduced because the sensitivity of thromboplastin reagents used for the measurement of prothrombin time (PT) is widely different and comparison among hospitals employing different reagents is virtually impossible. In 1989 and 1994, therapeutic guidelines for monitoring oral anticoagulant were published in the western countries, but they might not fit Asians who were not so prone to thrombotic diseases compared to Caucasians. Therefore, we are in need of establishing the optimal therapeutic range of oral anticoagulant therapy for Japanese. Before we proceed to do so, the verification of the reliability of ISI/INR system is mandatory. In this study we simultaneously measured the plasma from 7 patients with warfarin therapy at 4 different institutions for PT seconds, PT-INR, thrombotest (TT) seconds and TT-INR. The comparison between these laboratories revealed clinically important variances between 4 laboratories even when PT was converted to PT-INR. The laboratory 1 and the laboratory 3 were using the same thromboplastin reagents for the measurement of PT. And PT (seconds) in both laboratories showed similar numbers, but when they converted into INR, the variances were of significance (maximum coefficient of variance 10.44). We investigated the reason why these differences occurred and found that the calculated PT seconds for normal control at the laboratory 3 were somewhat larger than those of other laboratories. If we assume that PT-INR is identical to TT-INR, the estimated PT (second) for normal control at the laboratory 3 can be calculated from TT-INR. And it was 10.56±0.10 seconds. This was nearly the same as the one which was used at the laboratory 1. In conclusion, there are some difficulties still existing to overcome before ISI/INR system will reliably be used. And we suggest attention should be given to the PT seconds used as normal control plasma.
PracticeBasic medicine
KeywordsProthrombin time, Thrombotest, INR, ISI, Anticoagulany.

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