Interpretation and management of INR results: A case history based survey in 13 countries

Real-life contemporary vitamin K antagonist is still associated with very low time in therapeutic range despite strict international normalized ratio monitoring: Results of big data analysis

WHAT IS KNOWN AND OBJECTIVE

This study aimed to determine the results of INR monitoring in patients on vitamin K antagonists (VKAs) and the time in therapeutic range (TTR) in 'real-world' settings.

METHODS

Retrospective analysis of 836,857 INR measurements performed in adults from February 2010 to August 2015 in two districts in the French Brittany region.

RESULTS

Of the 836,857 INR measurements, 94.9% were ordered by general practitioners and 2.0% by cardiologists. The number of tests increased by 10-year age categories up to the age-group of 80-90 years. The number of INR measurements increased from 169,636 in 2011 to 176,184 in 2012, but then decreased slightly to 162,597 in 2013 and 164,427 in 2014. Mean coefficient of variation of INR was 19.0%, and mean TTR was 29.0%. TTR was higher in women than in men (31% vs. 18%), in older than in younger patients (19.1% at 40 years and 38.6% at 100 years) and in patients with arrhythmias than in those with deep vein thrombosis/pulmonary embolism (44.4% versus 19.4%) (p < 10^-5 for each comparison). Median interval between INR measurements was 14 days [7-28]; it was prolonged in men vs women, rural vs urban regions, older vs younger patients and when requested by GPs vs cardiologists. The interval was shorter for patients with INR outside the therapeutic range versus patients with INR within the therapeutic range (9 days [5-21] vs. 18 days [10-29], p < 10^-10 ).

WHAT IS NEW AND CONCLUSION

VKAs are still frequently prescribed in this era of direct oral anticoagulants. The low TTR cannot be explained by inadequate INR monitoring.

Informatics External Quality Assurance (IEQA) Down Under: evaluation of a pilot implementation

External quality assurance (EQA) provides ongoing evaluation to verify that laboratory medicine results conform to quality standards expected for patient care. While attention has focused predominantly on test accuracy, the diagnostic phases, consisting of pre- and post-laboratory phases of testing, have thus far lagged in the development of an appropriate diagnostic-phase EQA program. One of the challenges faced by Australian EQA has been a lack of standardisation or “harmonisation” resulting from variations in reporting between different laboratory medicine providers. This may introduce interpretation errors and misunderstanding of results by clinicians, resulting in a threat to patient safety. While initiatives such as the Australian Pathology Information, Terminology and Units Standardisation (PITUS) program have produced Standards for Pathology Informatics in Australia (SPIA), conformity to these requires regular monitoring to maintain integrity of data between sending (laboratory medicine providers) and receiving (physicians, MyHealth Record, registries) organisations’ systems. The PITUS 16 Informatics EQA (IEQA) Project together with the Royal College of Pathologists of Australasia Quality Assurance Programs (RCPAQAP) has created a system to perform quality assurance on the electronic laboratory message when the laboratory sends a result back to the EQA provider. The purpose of this study was to perform a small scale pilot implementation of an IEQA protocol, which was performed to test the suitability of the system to check compliance of existing Health Level-7 (HL7 v2.4) reporting standards localised and constrained by the RCPA SPIA. Here, we present key milestones from the implementation, including: (1) software development, (2) installation, and verification of the system and communication services, (3) implementation of the IEQA program and compliance testing of the received HL7 v2.4 report messages, (4) compilation of a draft Informatics Program Survey Report for each laboratory and (5) review consisting of presentation of a report showing the compliance checking tool to each participating laboratory.

Essential aspects of external quality assurance for point-of-care testing

External quality assurance (EQA) or proficiency testing for point-of-care (POC) testing is in principle similar to EQA for larger hospital laboratories, but the participants are different. The participants are usually health care personnel with little or no knowledge of laboratory medicine. The implication of this is that the EQA provider has to a) convince the participants that participation in EQA schemes are important, b) be able to circulate materials with reasonable time intervals, c) produce feedback reports that are understandable, and d) offer help and guidance to the participants when needed. It is also important that EQA for POC testing e) address the pre-examination, the examination and the post-examination processes, and f) that schemes for measurement procedures using interval or ordinal scale are offered. The aim of the present paper is to highlight important issues of these essential aspects of EQA for POC testing.

External Quality Assessment beyond the analytical phase: an Australian perspective

External Quality Assessment (EQA) is the verification, on a recurring basis, that laboratory results conform to expectations for the quality required for patient care. It is now widely recognised that both the pre- and post-laboratory phase of testing, termed the diagnostic phases, are a significant source of laboratory errors. These errors have a direct impact on both the effectiveness of the laboratory and patient safety. Despite this, Australian laboratories tend to be focussed on very narrow concepts of EQA, primarily surrounding test accuracy, with little in the way of EQA programs for the diagnostic phases. There is a wide range of possibilities for the development of EQA for the diagnostic phases in Australia, such as the utilisation of scenarios and health informatics. Such programs can also be supported through advances in health information and communications technology, including electronic test ordering and clinical decision support systems. While the development of such programs will require consultation and support from the referring doctors, and their format will need careful construction to ensure that the data collected is de-identified and provides education as well as useful and informative data, we believe that there is high value in the development of such programs. Therefore, it is our opinion that all pathology laboratories should strive to be involved in an EQA program in the diagnostic phases to both monitor the diagnostic process and to identify, learn from and reduce errors and near misses in these phases in a timely fashion.

Point-of-care testing (POCT) and evidence-based laboratory medicine (EBLM) - does it leverage any advantage in clinical decision making?

Point-of-care testing (POCT) is the analysis of patient specimens outside the clinical laboratory, near or at the site of patient care, usually performed by clinical staff without laboratory training, although it also encompasses patient self-monitoring. It is able to provide a rapid result near the patient and which can be acted upon immediately. The key driver is the concept that clinical decision making may be delayed when samples are sent to the clinical laboratory. Balanced against this are considerations of increased costs for purchase and maintenance of equipment, staff training, connectivity to the laboratory information system (LIS), quality control (QC) and external quality assurance (EQA) procedures, all required for accreditation under ISO 22870. The justification for POCT depends upon being able to demonstrate that a more timely result (shorter turnaround times (TATs)) is able to leverage a clinically important advantage in decision making compared with the central laboratory (CL). In the four decades since POCT was adapted for the self-monitoring of blood glucose levels by subjects with diabetes, numerous new POCT methodologies have become available, enabling the clinician to receive results and initiate treatment more rapidly. However, these instruments are often operated by staff not trained in laboratory medicine and hence are prone to errors in the analytical phase (as opposed to laboratory testing where the analytical phase has the least errors). In some environments, particularly remote rural settings, the CL may be at a considerable distance and timely availability of cardiac troponins and other analytes can triage referrals to the main centers, thus avoiding expensive unnecessary patient transportation costs. However, in the Emergency Department, availability of more rapid results with POCT does not always translate into shorter stays due to other barriers to implementation of care. In this review, we apply the principles of evidence-based laboratory medicine (EBLM) looking for high quality systematic reviews and meta-analyses, ideally underpinned by randomized controlled trials (RCTs), looking for evidence of whether POCT confers any advantage in clinical decision making in different scenarios.

How well do general practitioners manage laboratory test results for patients with diabetes mellitus and cardiovascular disease?: A systematic review

Purpose

To evaluate how well general practitioners (GPs) manage and respond to laboratory results for patients with diabetes mellitus (DM) and cardiovascular disease (CVD).

Data sources

MEDLINE, CINAHL, Embase, EBM reviews, ProQuest and Scopus.

Study selection

Peer-reviewed journal articles published between 2000 and 2015 that assessed GPs' management of laboratory results for patients with DM or CVD.

Data extraction

Study design and demographics, laboratory tests and key findings relating to GP management of laboratory results were extracted from studies.

Results of data synthesis

Thirteen articles were included, comprising seven studies which utilized surveys, four observational studies, one cohort study and one randomized controlled trial. Findings indicate that GPs often overestimate the risk of complications associated with DM and CVD based on laboratory results and have unrealistically high expectations regarding the precision of laboratory tests. Considerable variation existed in the use of repeat testing for diagnostic confirmation and in GPs' identification of the difference between two consecutive results required to indicate a change in patient condition. GPs also often failed to initiate appropriate treatment for patients with DM and CVD based on laboratory results. Feedback to GPs about their test ordering patterns and educational messages on laboratory results improved clinical outcomes.

Conclusion

Evidence about how well GPs manage results and its impact on patient outcomes remains weak and inconclusive. This review identified a number of areas where interventions could support GPs to improve the interpretation and management of laboratory test results, including feedback to GPs and educational messages on test result reports.

Warfarin monitoring in nursing homes assessed by case histories. Do recommendations and electronic alerts affect judgements?

PURPOSE

Older adults treated with warfarin are prone to complications, and high-quality monitoring is essential. The aim of this case history based study was to assess the quality of warfarin monitoring in a routine situation, and in a situation with an antibiotic-warfarin interaction, before and after receiving an electronic alert.

MATERIALS AND METHODS

In April 2014, a national web-based survey with two case histories was distributed among Norwegian nursing home physicians and general practitioners working part-time in nursing homes. Case A represented a patient on stable warfarin treatment, but with a substantial INR increase within the therapeutic interval. Case B represented a more challenging patient with trimethoprim sulfamethoxazole (TMS) treatment due to pyelonephritis. In both cases, the physicians were asked to state the next warfarin dose and the INR recall interval. In case B, the physicians could change their suggestions after receiving an electronic alert on the TMS-warfarin interaction.

RESULTS

Three hundred and ninety eight physicians in 292 nursing homes responded. Suggested INR recall intervals and warfarin doses varied substantially in both cases. In case A, 61% gave acceptable answers according to published recommendations, while only 9% did so for case B. Regarding the TMS-warfarin interaction in case history B, the electronic alert increased the percentage of respondents correctly suggesting a dose reduction from 29% to 53%. Having an INR instrument in the nursing home was associated with shortened INR recall times.

CONCLUSIONS

Practical advice on handling of warfarin treatment and drug interactions is needed. Electronic alerts as presented in electronic medical records seem insufficient to change practice. Availability of INR instruments may be important regarding recall time.

Critical laboratory values in hemostasis: toward consensus

The term "critical values" can be defined to entail laboratory test results that significantly lie outside the normal (reference) range and necessitate immediate reporting to safeguard patient health, as well as those displaying a highly and clinically significant variation compared to previous data. The identification and effective communication of "highly pathological" values has engaged the minds of many clinicians, health care and laboratory professionals for decades, since these activities are vital to good laboratory practice. This is especially true in hemostasis, where a timely and efficient communication of critical values strongly impacts patient management. Due to the heterogeneity of available data, this paper is hence aimed to analyze the state of the art and provide an expert opinion about the parameters, measurement units and alert limits pertaining to critical values in hemostasis, thus providing a basic document for future consultation that assists laboratory professionals and clinicians alike. KEY MESSAGES Critical values are laboratory test results significantly lying outside the normal (reference) range and necessitating immediate reporting to safeguard patient health. A broad heterogeneity exists about critical values in hemostasis worldwide. We provide here an expert opinion about the parameters, measurement units and alert limits pertaining to critical values in hemostasis.

How to manage warfarin therapy

Long-term treatment with warfarin is recommended for patients with atrial fibrillation at risk of stroke and those with recurrent venous thrombosis or prosthetic heart valves. Patient education before commencing warfarin - regarding signs and symptoms of bleeding, the impact of diet, potential drug interactions and the actions to take if a dose is missed - is pivotal to successful use. Scoring systems such as the CHADS2 score are used to determine if patients with atrial fibrillation are suitable for warfarin treatment. To rapidly achieve stable anticoagulation, use an age-adjusted protocol for starting warfarin. Regular monitoring of the anticoagulant effect is required. Evidence suggests that patients who self-monitor using point-of-care testing have better outcomes than other patients.