A Comprehensive Analysis of Metrological Traceability Tools for Urine Albumin Measurements

Urine albumin (UA) concentration is a critical biomarker of kidney disease and broad vascular damage, with an important diagnostic and prognostic role. However, nonstandardized UA measurement procedures are still used in medical laboratories. Much progress toward providing tools for standardizing UA measurements has been made in the past 17 years. This report provides a comprehensive analysis of the current status and availability of reference measurement system components for UA measurement, including recommendations on how to improve standardization and highlighting some important aspects that still require clarification, such as understanding in detail the interchangeability among all available secondary certified reference materials (CRMs) and the establishment of an analytical performance specification that is medically suitable. The presented analysis and related recommendations can help the international groups that are working on providing CRMs (both pure substance-based and commutable matrix-based) and reference measurement procedures for standardization of UA measurements. This information is also useful for in vitro diagnostic manufacturers when introducing the metrological traceability of UA measurement procedures to the International System of Units in the near future.