Harmonization of Test Results: What Are the Challenges; How Can We Make It Better?

Abstract

Laboratory test results are used to inform decisions on the diagnosis and treatment of disease. Consistent and comparable results from different measurement procedures are important for developing clinical practice guidelines and for those guidelines to be applied to decisions about patient care. ISO document 17511:2003 ( In vitro diagnostic medical devices -- Measurement of quantities in biological samples -- Metrological traceability of values assigned to calibrators and control materials ) states that calibration of routine clinical laboratory measurement procedures be traceable to higher-order reference materials and reference measurement procedures. Such traceability can achieve consistent and comparable results that are sustainable over time and among different measurement procedures. The terms “standardized” and “harmonized” are frequently used interchangeably to refer to the condition in which results are consistent and comparable among different measurement procedures. “Standardized” refers to the condition in which calibration is traceable to a reference measurement procedure that is typically calibrated with an appropriate reference material. There are situations in which the reference measurement procedure defines the analyte without any primary reference material (e.g., enzyme activity). Standardization has the advantage of trustworthy reproducibility over time and location, because the reference measurement procedure provides a stable anchor for calibration traceability of routine clinical laboratory procedures. “Harmonized” is a more general term. It may include the standardized condition, but it also includes the condition in which results are consistent and comparable in the absence of a reference measurement procedure. The process of harmonization typically depends on the availability of a suitable reference material that can be used as a common calibrator among routine clinical laboratory measurement procedures. Despite the availability of reference measurement procedures and reference materials, results for many analytes are neither consistent nor comparable when measured with different clinical laboratory procedures. In this Q&A, experts in harmonization of test results offer their …