Investigation and analysis of reference intervals of routine clinical chemistry assays in China

Abstract

Objective To describe upper and lower limits and their sources of reference intervals in routine chemistry assays and to make a comparison between routine and dry chemistry in these aspects.Methods The data of reference intervals were collected,which come from the third run of 2010 External Quality Assessment (EQA) programs in routine and dry chemistry performed by National Center for Clinical Laboratories(NCCL).All data from maternal and child care service center,children's hospital and corporations were excluded.Then all the abnormal values and errors (for instance,the lower limit was higher than the upper one or the upper limit was as the same as the lower one,etc.) were eliminated,either.Data statistics was performed by SPSS 13.0 referring to upper and lower limits of reference intervals and sources of 24 routine chemistry assays ( including serum potassium and serum sodium,etc).Comparison was made between routine and dry chemistry in these aspects in 23 assays.Data from adult men were reported when gender difference was present.Results The three main sources of reference intervals were National Guide to Clinical Laboratory Procedures, instructions of reagent manufactures and determined by their own laboratory.In comparison of reference intervals between routine and dry chemistry,6 assays had statistical significant difference in both upper limits and lower ones while,4 assays in one-sided limits and 13 assays were not statistically significant in both limits.Conclusions The reference intervals of routine chemistry have big differences among institutions and the sources of them are various.Only a few assays have statistical significant difference in routine and dry chemistry among medical institutions,it might be discussed in further study whether the statistical results have clinical values.In order to achieve the result agreement among clinical assays,all the laboratories must share the common reference intervals on the basis of standardization. Key words: Clinical chemistry tests; Diagnostic tests, routine; Reference values; Quality control