The concept of metrological traceability in laboratory medicine has increasingly received considerable recognition worldwide.The Consultative Committee for Amount of Substance (CCQM) which concerned international comparisons and establishment of international equivalence between national laboratories had organized international comparison CCQM-P77a: determination of serum cortisol in 2006.National Institute of Metrology (NIM) took part in the comparison as the representative of China and received good performance according to the results published by CCQM.
