Abstract:

Objective To establish the regional reference intervals of 5 items for thyroid function by chemiluminescence,and to verify the regional reference intervals used directly or not.Methods According to the Clinical and Laboratory Standards Institute（CLSI） C28-A3 and the reference intervals supplied by LIAISON specification,free triiodothyronine（FT₃）,free thyroxine（FT₄）,triiodothyronine（T₃）,thyroxine（T₄） and thyroid stimulating hormone（TSH） were determined by LIAISON chemiluminescence assay system in 5 070 healthy adults,and the reference intervals supplied by manufacturers were verified with 20 normal cases. The differences for age and sex were analyzed. The reference intervals were established according to 98% confidence intervals （95% confidence interval for TSH）.Results The overall reference intervals of FT₃,FT₄,T₃,T₄ and TSH were 3.34-6.35 mmol/L,10.28-20.96 mmol/L,0.67-1.82 μg/L,52.16-133.92 μg/L and 0.31-5.25 mIU/L. The levels of FT₃,FT₄ and TSH had statistical significance between males and females（P<0.05）. In males,the level of FT₃ had statistical significance between before and after 51 years old（P=0.000）. In females,the statistical significance appeared before and after 61 years old（P=0.000）. In males and females,the level of FT₄ had statistical significance between before and after 71 years old（P<0.05）. The reference intervals of T₃ and TSH could not pass the verification,when the reference intervals were verified by 20 normal cases. So,the reference intervals of T₃ and TSH must be re-established. Conclusions Reference intervals supplied by manufacturers are wide relatively. The reference intervals could meet related requirements basically except those of T₃ and TSH. However,there is no difference for ages and sex. Laboratories should establish individual reference intervals for different ages and sex in order to provide a reference for reliable sensitive diagnosis.

Key words: Thyroid hormones, Pituitary-thyroid axis, Reference interval, Yuxi, Adults