Accredia / Accredited services / Reference measurements

Reference measurements

Analytical accuracy

Accredited calibration laboratories provide laboratory medicine and measurement services which fulfill the traceability requirements.

The results of tests undertaken by means of laboratory medicine influence a high number of clinical decisions. Doctors, patients and users of services expect to be able to count on these results, independently of the applied method, although in some cases there may be variations between the methods and this can affect the interpretation of the clinical result.

Traceability, backed up by accreditation against the standards ISO/IEC 17025 and ISO 15195, applicable to laboratory medicine, is of crucial importance for reducing margins of variability and, thus, increasing the accuracy of analyses and diagnoses.

The objectives

Respecting the traceability requirements, the reference measurements have the aim of reducing variability among methods in order to:

  • increase the safety of patients;
  • increase the trust of the general public;
  • provide continuous improvement of the level of quality and professionalism of the services provided.

Metrological traceability

Metrological traceability is the property of a measurement result which may be related to a reference by means of an uninterrupted chain of documented calibrations.


The traceability of values of RMs, calibrations and materials of control must be ensured by means of the available traceability reference, measurement procedures and/or traceability references of a higher order.


The principles for establishing metrological traceability are defined in ISO 15195 “Requirements for reference measurement laboratories – diagnostic medical devices – measurements of quantities in biological samples, metrological traceability of calibrated values and control materials”.


The components include RMs (calibrators) and measurement procedures, both of which exist at different levels.

Accredited laboratories for RMs

Reference measurements in laboratory medicine are provided by laboratories accredited according to the ISO 17025 and ISO 15195, on the requirements for reference measurement laboratories which, in the laboratory medicine sector, provide the metrological traceability. These standards do not apply to clinical laboratories that perform daily grind measurements.