Quality assurance for point‐of‐care testing of oral anticoagulation: a large‐scale evaluation of the Hemochron Junior Signature Microcoagulation System

Abstract

We report the first large-scale evaluation of the Hemochron Junior Signature (HJS) Microcoagulation System for community monitoring of oral anticoagulation and establishment of a programme of internal and external quality assurance. Over 1600 HJS results, with a simultaneous venous sample for central analysis, were obtained over a 19 month period. Monitoring of an initial period of HJS results (n = 135) revealed an International Normalized Ratio (INR) over estimation (mean +1.05), with only 27% of results within 0.5 of the central laboratory INR. A correction factor was introduced which reduced the INR bias to +0.07 and improved the percentage of results within 0.5 of the central laboratory INR to 76% (n = 353). A revised correction factor was later introduced to adjust for an under estimation at higher INR values. This changed the INR bias to -0.05, with 76% of results within 0.5 of the central laboratory INR (n = 1174). Local external quality assurance samples were distributed monthly with a total of 791 samples during the study period. 84% of test results were within 15% of the median value (range 73-97% per month). These results emphasize the value of a robust quality assurance programme when using point-of-care devices for community monitoring of oral anticoagulation.

Limits of agreement between measures obtained from standard laboratory and the point-of-care device Hemochron Signature Elite® during acute haemorrhage

“…15 In another work, the use of a correction factor was required to reduce the bias. 17 A more recent publication observed an overestimation of INR values ,3 and underestimation of values .4, which was associated with a clinical therapeutic impact in 31% of cases. 26 Against other POC devices that have been tested in acute haemorrhage, 11 18 26 the HC w compares unfavourably.…”

Patients' perspectives on self-testing of oral anticoagulation therapy: Content analysis of patients' internet blogs

“…Research studies have shown mixed findings in relation to the cost effectiveness of monitoring oral coagulations [44]. Lafata et al [45] have reported that patient self-monitoring (PSM) is not cost effective compared to health professional monitoring (HPM) while Taborski et al [46], Cheung et al [47] and Regier et al [48] reported that PSM is indeed more cost effective than the HPM.…”

Monitoring of haemostasis in liver transplantation: comparison of laboratory based and point of care tests

“…These authors compared thrombelastography-and thrombelastometry-guided transfusion protocols and concluded that different transfusion practices resulted. Concerning the Hemochron Signature device, only four publications seem to report its use for monitoring of heparin treatment and oral anticoagulation [11,[13][14][15]. No information, however, is available on the use of the device in liver disease.…”