Abstract: Objective：To develop a quantitative evaluation method for G-band chromosome preparation. Methods：233 subjects were randomly selected for peripheral blood karyotyping analysis in our hospital from Sep 2016 to Mar 2017. For each sample，both conventional method and high resolution chromosome method were used for cell culture，harvest and karyotype analysis. Quality evaluation score was obtained using 15 quality assessment bands. This score was then compared between the low-median resolution group and the high resolution group. Results：The score of high resolution group was higher than that of group （P＜0.05）. The chromosomes of high resolution group were clear, rich in stripes，moderate in length and dispersion. Conclusions：The quality evaluation based on 15 quality assessment bands can be used to quantify the effect of chromosome preparation，as the internal quality control in laboratory and external quality assessment among laboratories of chromosome karyotyping analysis, suggesting its clinical value in the diagnosis of chromosomal diseases.

Key words: Chromosome banding, Cell cycle, Fluorouracil, Karyotyping