Abstract:

Objective To prepare five frozen pooled human serum samples as secondary reference materials for uric acid（UA）,which were used to validate trueness of routine methods. Methods Five UA concentrations of fasting fresh serum samples without lipemia,hemolysisorcholoplania were collected selectively,mixed and centrifuged. The supernatants were filtrated,allotted,sealed and stored at -70 °C. The homogeneity and stability of the five frozen pooled serum samples were evaluated according to Reference Materials-General and Statistical Principles for Certification (ISO Guide 35 for short). The materials were assigned values by three candidate reference laboratories. The fixed values of the five serum samples presented as target value ± total uncertainty（u_CRM）. Commutability of the five serum samples was assessed according to the National Committee for Clinical Laboratory Standards EP14-A2. Results The five frozen pooled serum samples were homogeneous（P>0.05）,and the variation between bottles was less than 1%. The stability of UA concentration at room temperature and 4 ℃ could meet the needs of daily use. The samples were stable for at least 115 days at -20 ℃ and 15 months at -70 ℃. The fixed valuesof the five frozen pooled serum samples for UA were (70.00±3.12),(281.67±4.69),(383.00±6.46),(431.00±9.95) and (520.00±12.10) μmol/L. The five frozen pooled serum samples had good commutability among 15 routine analytical systems. Conclusion The fivefrozen pooled serum samples are homogeneous,stable,commutable and well assigned,which can be recommended as secondary reference materials for UA.

Key words: Uric acid, Homogeneity, Stability, Commutability