To describe the reference intervals and their sources of tumor markers in clinical laboratories all over China.And make a comparison of difference between different testing systems.

The questionnaires about reference intervals of tumor markers testing were distributed to participants.The information was collected by external quality assessment software system based on website, which including upper and lower limits, sources, validation information and testing systems. The analytes were AFP, CEA, total-PSA, CA125, CA153, CA199, ferritin and free-PSA. The participants were classified according to the testing systems they used. The mean, median, maximum and minimum of each group were calculated using Microsoft Excel 2007.The difference of reference intervals between different testing systems were compared by Kruskal-Wallis test.

The main source of reference intervals was instructions of testing system manufactures (83.1% for mean of 8 ratios). The next in sequence were instructions of reagent manufactures(8.4% for mean), National Guide to Clinical Laboratory Procedures (4.6% for mean), determined by their own laboratory(2.0% for mean) and the rest (1.9% for mean). There were 48.0% (1 906/3 967) of analytes whose reference intervals had been validated.Difference of reference intervals which was with P value of Kruskal-Wallis test with <0.05 was found between different testing system groups except the upper limit of free prostate specific antigen(PSA).

Most clinical laboratories establish the reference intervals of tumor markers on the basis of instructions of testing system manufactures. The reference intervals among different testing systems have statistically significance.(Chin J Lab Med, 2015, 38: 349-352)

Tumor markers, biological; Reference values; Quality control