Objective To evaluate the stability of the total bile acid reagent after opening the improved bottles.Methods We analyzed the total bile acid reagents in automatic biochemistry respectively by using the common reagent bottles and the improved reagent bottles.Observe daytime variation of CV and trend changes of high,medium mixed complex-value serum and reagent blank test results.Then t test was applied.Results (1)The change trend of the improved reagent bottles was significantly slower than that of the common reagent bottles,(2)The total deviations of common reagent bottles before and after monitoring were-20.37% and-22.09% respectively.Total deviations of the improved reagent bottles were 3.77% and-1.16% respectively,(3)The daytime variations of the common reagent bottles in complex-value were 9.27% and 9.32% respectively;the improved reagent bottles were 3.38% and 2.03% respectively;(4)The reagent blank with improved reagent bottles decline significantly slower than common reagent bottles;(5)The measured result of t test of the two kinds reagent bottles in the monitoring period was t=4.889,P0.01,the result there was significantly different.Conclusion The impvored reagent bottles have good performance to slow down the decay of total bile acid reagentand,and it′s suitable for extending the period of reagents′ validity.It can significantly reduce daytime variation.