Performance of the microINR Point-of-Care System: A Multicenter Clinical Trial

Introduction There are limited publications about the microINR point-of-care (POC) system (iLine Microsystems). The current microINR POC system was compared with the ACL TOP 500 laboratory analyzer (Instrumentation Laboratory) and with the CoaguChek XS POC system (Roche Diagnostics). Methods This study was performed at three United States medical centers. Sixty-eight nonanticoagulated normal donors and 245 warfarin anticoagulated patients were included. Testing was performed in duplicate using capillary blood samples for the POC systems and venous blood samples for the laboratory testing. Accuracy and imprecision were assessed. Results Comparing microINR to ACL revealed a correlation coefficient (r) of 0.973, a slope of 1.00 (95% confidence interval [CI], 0.97–1.03), and an intercept of 0.08 (95% CI, 0.04–0.15). When compared with the CoaguChek XS, r was 0.977 with a slope of 0.92 (95% CI, 0.89–0.94) and an intercept of 0.15 (95% CI, 0.08–0.19). Predicted bias values at international normalized ratio (INR) 2.0, 3.5, and 4.5 were ≤ 5% against both references. Agreement with ACL was 97, 95, and 100% for the INR ranges of < 2.0 ± 0.40, 2.0 to 4.5 ± 20%, and ≥ 4.5 ± 25%, respectively. Agreement for the combined INR ranges was 96% against ACL and > 96% against the CoaguChek XS. The coefficient of variation of the microINR was 5.03% for INR < 2.0 and 4.68% for the therapeutic INR range 2.0 to 3.5. Conclusion The microINR results demonstrate adequate imprecision and accuracy to both ACL and CoaguChek XS. This indicates that monitoring INR by this microINR POC system is reliable and acceptable for the management of warfarin therapy.

Accuracy assessment of consecutive test strip lots for whole blood INR point-of-care instruments: clarifying the role of frozen plasma pools

Background In the Netherlands, each new lot of test strips for the CoaguChek XS is validated by a group of collaborating centers. The purpose of this study was to assess the accuracy of the international normalized ratio (INR) measured with consecutive test strip lots and the suitability of frozen plasma pools for accuracy evaluation. Methods Each year, a particular lot of CoaguChek XS test strips is used as reference lot. The reference lots have been validated with the International Standard for thromboplastin rTF/09, yielding a mathematical relationship (R1) between reference lot INR and International Standard INR. New lots are compared to the reference lot using patients’ capillary blood samples, yielding a relationship (R2) between the new lot INR and the reference lot INR. INRs of the blood samples were within the 1.5–4.5 interval. In parallel, three frozen plasmas pools are analyzed with the test strips. The distance of each plasma point to the line of relationship R2 was assessed. Results Fifty-four test strip lots have been evaluated during 3 years (2014–2016). Mean INR differences between test strip lot and International Standard rTF/09 varied between −0.14 and +0.20 (−4% and +8%, respectively). A positive trend with strip lot sequence number was observed (p<0.001). In several cases, the distance of the frozen plasmas to the whole blood relationship (R2) was greater than the critical value for commutability. Conclusions Using whole blood, all evaluated test strip lots met the analytical bias criterion of ±10%. Frozen plasma pools behave differently compared to whole blood and are not suitable for assessing absolute accuracy of new CoaguChek XS test strips.

Assessment of the CoaguChek-XS portable prothrombin time point-of-care analyzer for horses

Coagulopathies in horses are common and potentially life-threatening. In equine field medicine, a portable point-of-care (POC) prothrombin time (PT) testing device could be useful to identify early changes in extrinsic clotting. The CoaguChek-XS (Roche Diagnostics) is a small, portable POC PT analyzer used in human medicine. Our preliminary study assessed the suitability of CoaguChek-XS for testing PT in horses and established the PT reference interval (PT RI) in healthy horses using this instrument. Blood samples collected from 102 healthy and ill horses were analyzed with the CoaguChek-XS and compared to a semi-automated coagulometric analyzer (SACA) as the gold standard. There was a significant positive correlation between the 2 measurement methods ( r = 0.765, p < 0.01), and very good agreement, with 97% of the samples falling within limits of agreement. The mean CoaguChek-XS PT coefficient of variation was 0.8%, indicating high precision. With high precision and good agreement with the coagulometric PT, the CoaguChek-XS should be further validated for PT measurement in horses.

НАЧАЛЬНЫЙ ЭТАП ТЕСТИРОВАНИЯ РАЗРАБАТЫВАЕМОГО АППАРАТА ДЛЯ ОПРЕДЕЛЕНИЯ МЕЖДУНАРОДНОГО НОРМАЛИЗОВАННОГО ОТНОШЕНИЯ

Протромбиновое время (ПТВ) – это лабораторный показатель, позволяющий оценить внешний путь свертывания крови (активность факторов I, II, V, VII и X). Для стандартизации результатов теста ПТВ введен показатель МНО. МНО = (ПТВ пациента/ПТВ 100%)МИЧ. Набирает популярность контроль МНО с помощью портативных коагулометров. На российском рынке представлены: CoaguChek XS, qLabs Electrometer. Главная проблема − их высокая стоимость и дороговизна в эксплуатации. Российские ученые давно задались вопросом импортозамещения. Однако, в литературе нет информации о тестировании разработок. При разработке экспериментальной модели для измерения МНО и ПТВ, мы руководствовались результатами литературного поиска по наукометрическим базам данных Elibrary, Scopus, PubMed и WoS с учетом предполагаемой стоимости разрабатываемой модели.Цель исследования. Провести начальный этап тестирования экспериментальной модели с сопоставлением полученных результатов с данными сертифицированной лаборатории.Материал и методы. Обследовано 70 пациентов (26 мужчин и 44 женщины), принимающих «Варфарин». Материал для измерения экспериментальной моделью – капиллярная кровь. В качестве тест-системы применяли тест-полоску qLabs® PT-INR Test Strip.Результаты. Разница ПТВ тестируемой модели и результатов сертифицированной лаборатории ± 1–2 секунды. ПТВ Протромбин-калибратора 13 сек. Протромбиновое отношение Протромбин-калибратора 1,0. Пациент №1. ПТВ на тестируемом аппарате 34 сек. МИЧ тробопластина на тест-полоске 1,0. МНО = (34 сек /13 сек × 1,0)1,0 = 2,62. Результат сертифицированной лаборатории: ПТВ 36 сек, МНО 2,86. Пациент №2. ПТВ на тестируемом аппарате 31 сек. МНО = (31 сек/13 сек × 1,0)1,0 = 2,38. Результаты сертифицированной лаборатории: ПТВ 32 сек, МНО 2,48.Вывод. Согласно представленным результатам, полученным в ходе тестирования разработанной портативной модели у пациентов, находящихся на варфаринотерапии, получены сопоставимые результаты ПТВ и МНО сертифицированной лабораторией.