The traceability of a measurement result refers to metrological traceability as defined by VIM. It relates the result to SI units or other agreed standards/references. Traceability is essential for comparability of analytical results and it is a strong requirement of ISO/IEC 17025. Traceability is achieved following good laboratory practice for. However it may be time consuming and expensive to calibrate all equipment. By time a laboratory should review its calibration and for stable equipment the calibration interval maybe extended by introducing control of status.

From Eurachem there is a Traceability guide and a leaflet. There is also a guide on Selection of reference materials. The picture below is from the leaflet

 

  Example of traceability to the SI - Temperature     The temperature of a sample can be traced back through a  chain of calibrations  to the  reference,  an SI value of temperature at 0   °  C. Drawing by Douglas Hasbun, Sweden,

Example of traceability to the SI - Temperature

The temperature of a sample can be traced back through a chain of calibrations to the reference, an SI value of temperature at 0 °C. Drawing by Douglas Hasbun, Sweden,