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

Technology-assisted self-testing and management of oral anticoagulation therapy: a qualitative patient-focused study

BACKGROUND

Oral anticoagulation therapy requires regular blood testing to ensure therapeutic levels are maintained and excessive bleeding/clotting is avoided. Technology-assisted self-testing and management is seen as one of the key areas in which quality of care can be improved whilst reducing costs. Nevertheless, levels of patient engagement in self-testing and management remain low. To date, little research emphasis has been placed on understanding the patients' perspectives for low engagement. The typical approach adopted by healthcare providers is to provide patient education programmes, with the expectation that individual patients will change their behaviour and adopt new self-care strategies. However, if levels of patient engagement are to be increased, healthcare providers must also develop a better understanding of how their clinical service provision is perceived by patients and make adaptations.

OBJECTIVE

To explore patient views, needs and expectations of an anticoagulation service and the self-testing and management services provided.

METHODS

Interviews were conducted with 17 patients who currently engage in international normalised ratio (INR) self-testing and management. Thematic coding and analysis were carried out on the interview transcripts.

RESULTS

Four high-level themes emerged from interviews: (i) role of clinic, (ii) motivations for self-testing, (iii) managing INR and (iv) trust. The clinic was seen as adding value in terms of specifying testing frequency, dosage profiles and calibrating equipment. Prompt communication from clinic to patient was also valued, although more personalised/real-time communication would help avoid feelings of isolation. Patients felt more in control as self-tester/managers and often took decisions about treatment adjustments themselves. However, some also manipulated their own test results to avoid 'unnecessary' interventions.

CONCLUSIONS AND RECOMMENDATIONS

More personalised/real-time communication, pragmatic and collaborative patient-clinician partnerships and recognition of expert patient knowledge and expertise are needed if increased levels of engagement with self-testing and management service provision is to be realised.

Reliability of a point-of-care device for international normalized ratio testing during the three surgical phases of orthotopic liver transplantation: a retrospective observational study

PURPOSE

To investigate the reliability of a point-of-care device, the HEMOCHRON(®) Jr. Signature, for measuring the international normalized ratio (INR) during the three surgical phases of liver transplantation.

METHODS

A retrospective review was performed on patients undergoing liver transplantation during July to December 2013. Thirty-one patients who had simultaneous laboratory and point-of-care INR readings from each phase of liver transplant surgery (paleohepatic, anhepatic, and neohepatic) were eligible for inclusion. Bland-Altman analysis, Spearman's rank correlation, and four quadrant plots were used to compare INR results from the point-of-care device (pocINR) with those from the laboratory (labINR).

RESULTS

Based on the Bland-Altman analysis, mean biases (95% prediction interval) were 0.10 (0.03 to 0.17), 0.19 (0.12 to 0.27), and 0.21 (0.01 to 0.43) for the paleohepatic, anhepatic, and neohepatic phases, respectively. The pocINR device showed a systematic underestimation of the labINR. The Spearman's rank correlation coefficients (95% confidence interval [CI]) were: Ρ = 0.90 (95% CI 0.80 to 0.95); Ρ = 0.92 (95% CI 0.71 to 0.93); and Ρ = 0.71 (95% CI 0.46 to 0.85), respectively. Direction-of-change analysis between the paleohepatic to anhepatic and the anhepatic to neohepatic phases showed strong concordance of 84% and, also considering the small bias between the measurements, supports the use of the pocINR device in the clinical management of liver transplant surgery.

CONCLUSION

Point-of-care INR was accurate prior to hepatic reperfusion, but reliability decreased in the neohepatic phase.

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

BACKGROUND

Rapid diagnosis of coagulopathy in the bleeding patient using point-of-care (POC) devices would be ideal. The Hemochron Signature Elite(®) (HC(®)) is a POC device that determines international normalized ratio (INR) and activated partial thromboplastin time (aPTT). The aim of the study was to evaluate the agreement for INR and aPTT between the HC(®) and standard laboratory values in acute haemorrhage.

METHODS

This was a single-centre observational prospective study including patients with acute haemorrhage. Laboratory INR and aPTT were compared with simultaneous measurements performed with the HC(®). The diagnostic performance of HC(®) was determined; bias and limits of agreement were calculated according to the method of Bland and Altman.

RESULTS

Seventy-two pairs of measurements from 39 patients were analysed. The bias between the INR-HC(®) and aPTT-HC(®) measurements and the central laboratory were 0.02 and -1.13, respectively. The Spearman's correlation coefficients for the INR-HC(®)/INR-lab and the aPTT-HC(®)/aPTT-lab were 0.68 and -0.29, respectively. Twenty-seven per cent of INR-HC(®) values and 89% of the aPTT-HC(®) values exceeded the predefined limits of agreement. The INR-HC(®) measurement identified patients with a central laboratory INR >1.5 with a sensitivity, specificity, and positive and negative predictive values of 83%, 70%, 76%, and 77%, respectively.

CONCLUSIONS

The results showed a lack of agreement between the INR-HC(®) and the aPTT-HC(®) measurements and the standard laboratory in the context of acute haemorrhage. The INR-HC(®) showed moderate performance as a decision-making tool to detect coagulopathy in the context of acute haemorrhage.

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

BACKGROUND

Patients on oral anticoagulant therapy (OAT) require regular testing of the prothrombin time (PT) and the international normalised ratio (INR) to monitor their blood coagulation level to avoid complications of either over or under coagulation. PT/INR can be tested by a healthcare professional or by the patient. The latter mode of the testing is known as patient self-testing or home testing. The objective of this study was to elicit patients' perspectives and experiences regarding PT/INR self-testing using portable coagulometer devices.

METHODS

Internet blog text mining was used to collect 246 blog postings by 108 patients, mainly from the USA and the UK. The content of these qualitative data were analysed using XSight and NVivo software packages.

RESULTS

The key themes in relation to self-testing of OAT identified were as follows: Patient benefits reported were time saved, personal control, choice, travel reduction, cheaper testing, and peace of mind. Equipment issues included high costs, reliability, quality, and learning how to use the device. PT/INR issues focused on the frequency of testing, INR fluctuations and individual target (therapeutic) INR level. Other themes noted were INR testing at laboratories, the interactions with healthcare professionals in managing and testing OAT and insurance companies' involvement in acquiring the self-testing equipment. Social issues included the pain and stress of taking and testing for OAT.

CONCLUSIONS

Patients' blogs on PT/INR testing provide insightful information that can help in understanding the nature of the experiences and perspectives of patients on self-testing of OAT. The themes identified in this paper highlight the substantial complexities involved in self-testing programmes in the healthcare system. Thus, the issues elicited in this study are very valuable for all stakeholders involved in developing effective self-testing strategies in healthcare that are gaining considerable current momentum particularly for patients with chronic illness.

Comparison of plasma with whole blood prothrombin time and fibrinogen on the same instrument

We compared plasma with whole blood (WB) international normalized ratio (INR) and fibrinogen using the same instrument and reagents. WBINRs were 50% higher than plasma INRs. After increasing the WB sample volume 40% and adjusting the International Sensitivity Index, WBINRs were similar to plasma INRs [adjusted WBINR = 0.99(plasma INR) - 0.02; r(2) = 0.98; n = 155], but the average difference in WB vs plasma INR was 4-fold higher than duplicate plasma INRs. Variation in hematocrit was a major determinant of the accuracy of the WBINR, with increased error at high INRs. The WB fibrinogen assay was highly dependent on the sample hematocrit (r(2) = 0.83), even after the sample volume was adjusted. Accurate WB fibrinogen measurements required a mathematical hematocrit correction. We conclude that WBINR and fibrinogen assays can be performed on point-of-care or automated analyzers, but sample volume must be adjusted to account for hematocrit. Accuracy is limited by variations in hematocrit with worsening accuracy for samples with high INRs or low fibrinogen levels.

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

During orthotopic liver transplanatation haemostasis is often disturbed and coagulation monitoring is mandatory. We compared the results obtained by whole blood prothrombin time and activated partial thromboplastin time assays (Hemochron) and thrombelastometry (ROTEM) 05) with laboratory coagulation assays (prothrombin time, activated partial prothrombin time, fibrinogen, and platelet count) in samples obtained during orthotopic liver transplantations. Determination of prothrombin time and activated partial prothrombin time using the Hemochron device showed good correlation with laboratory coagulation assays (r = 0.912, p < 0.001, and r = 0.794, p < 0.001). Maximum clot firmness as determined by thrombelastometry correlated well with platelet count (r = 0.779, p < 0.001) and, to a lesser degree, with fibrinogen concentration (r = 0.590, p < 0.001). During orthotopic liver transplantation, prothrombin time and activated partial prothrombin time can be reliably determined by the Hemochron device, while thrombelastometry allows assessment of platelet count and fibrinogen concentration.