Glycemic Control in the 12 Months following a Change to SI Hemoglobin A1c Reporting Units

HbA1c method performance: The great success story of global standardization

Diagnosing and monitoring the treatment of people with diabetes is a global issue and uses considerable resources in laboratories and clinics worldwide. Hemoglobin A1c (HbA1c) has been the mainstay of monitoring glycemic control in people with diabetes for many years and more recently it has been advocated as a diagnostic tool for type 2 diabetes mellitus (T2DM). Good analytical performance is key to the successful use of any laboratory test, but is critical when using the test to diagnose disease, especially when the potential number of diagnoses could exceed 500 million people. Very small variations in bias or increased imprecision could lead to either a missed diagnosis or overdiagnosis of the disease and given the scale of the global disease burden, this could mean erroneous categorization of potentially millions of people. Fundamental to good performance of diagnostic testing is standardization, with defined reference materials and measurement procedures. In this review, we discuss the historical steps to first harmonize HbA1c testing, followed by the global standardization efforts and provide an update on the current situation and future goals for HbA1c testing.

Current Evidence and Future Perspectives on the Effective Practice of Patient-Centered Laboratory Medicine

BACKGROUND

Systematic evidence of the contribution made by laboratory medicine to patient outcomes and the overall process of healthcare is difficult to find. An understanding of the value of laboratory medicine, how it can be determined, and the various factors that influence it is vital to ensuring that the service is provided and used optimally.

CONTENT

This review summarizes existing evidence supporting the impact of laboratory medicine in healthcare and indicates the gaps in our understanding. It also identifies deficiencies in current utilization, suggests potential solutions, and offers a vision of a future in which laboratory medicine is used optimally to support patient care.

SUMMARY

To maximize the value of laboratory medicine, work is required in 5 areas: (a) improved utilization of existing and new tests; (b) definition of new roles for laboratory professionals that are focused on optimizing patient outcomes by adding value at all points of the diagnostic brain-to-brain cycle; (c) development of standardized protocols for prospective patient-centered studies of biomarker clinical effectiveness or extraanalytical process effectiveness; (d) benchmarking of existing and new tests in specified situations with commonly accepted measures of effectiveness; (e) agreed definition and validation of effectiveness measures and use of checklists for articles submitted for publication. Progress in these areas is essential if we are to demonstrate and enhance the value of laboratory medicine and prevent valuable information being lost in meaningless data. This requires effective collaboration with clinicians, and a determination to accept patient outcome and patient experience as the primary measure of laboratory effectiveness.

Harmonization: the sample, the measurement, and the report

Harmonization of clinical laboratory results means that results are comparable irrespective of the measurement procedure used and where or when a measurement was made. Harmonization of test results includes consideration of pre-analytical, analytical, and post-analytical aspects. Progress has been made in each of these aspects, but there is currently poor coordination of the effort among different professional organizations in different countries. Pre-analytical considerations include terminology for the order, instructions for preparation of the patient, collection of the samples, and handling and transportation of the samples to the laboratory. Key analytical considerations include calibration traceability to a reference system, commutability of reference materials used in a traceability scheme, and specificity of the measurement of the biomolecule of interest. International organizations addressing harmonization include the International Federation for Clinical Chemistry and Laboratory Medicine, the World Health Organization, and the recently formed International Consortium for Harmonization of Clinical Laboratory Results (ICHCLR). The ICHCLR will provide a prioritization process for measurands and a service to coordinate global harmonization activities to avoid duplication of effort. Post-analytical considerations include nomenclature, units, significant figures, and reference intervals or decision values for results. Harmonization in all of these areas is necessary for optimal laboratory service. This review summarizes the status of harmonization in each of these areas and describes activities underway to achieve the goal of fully harmonized clinical laboratory testing.