Abstract:

Objective Discuss the clinical value of the automatic dropping in chromosome preparation by comparing the differences between the automatic and manual dropping of amniotic fluid cell chromosomes. Methods The amniotic fluid cells were harvested routinely and automatically. Under the same settings，the amniotic fluid cells were dropped by the metaphase chromosome auto ⁃ spreader and the manual method，respectively. The two methods were compared in terms of mitotic index，ratio of chromosome dispersion area，effective karyotype rate and chromosome band level. Results A total of 47 amniotic fluid specimens were included and dropped into 376 slides. 1066 mitotic phases were analyzed effectively，of which 650 were obtained by metaphase spreader and 416 were obtained manually. As a result，the mitotic index and the quality of the karyotype harvested by the automatic dropping were statistically significantly higher than that of the manual dropping（P < 0.0001）. Meanwhile，the degree of chromosome dispersion obtained by the two methods was equivalent，without statistically significant differ⁃ ences between the methods. As for the efficiency，the time by the manual method was significantly shorter than the automatic dropping（P < 0.01）. Conclusion The automatic dropping for chromosome preparation is better in quality and stability than the manual method，and thus it is worthy of clinical application.

Key words:

chromosomes, amniotic fluid, mitotic index, chromosome dropping, chromosome preparation