The IFCC has recently approved a reference measurment procedure for measuring the propertf often designated "HbA1c". This analytially specific procedure involving single molecular species allows calculation of measurement results as "amount-of-substance fraction" rather than mass fraction. In addition it provides well-defined metrological traceability to the International System of Units (SI).
As the numerical values of the measurement results will change with the new measurement proceddure, it is timely to reconsider the current termsfor the property in terms of system, component, and kind-of-property, as well as the expression of the measurement result.