Infertility & Sexual Dysfunction(구연) (E-191) A Modified Nomogram to Predict Need of Karyotype Analysis in Infertile Men Urology, Hanyang University Medical Center, Urology, Hanyang University Medical Center, Urology, Hanyang University Medical Center, Urology, CHA Gangnam Medical Center, CHA University, Urology, CHA Gangnam Medical Center, CHA University, Urology, CHA Fertility Center Seoul Station, CHA University School of Medicine Young Eun Yoon, Sung Yul Park, Hong Sang Moon, Dong Suk Kim, Seung-Hun Song, Dae Keun Kim Background: Karyotype analysis in infertile male patient plays an important role in work up to find a possible underlying cause. The EAU guideline recommend karyotype analysis for sperm concentration less than 10 million/ml, and a Ventimiglia nomogram had been developed to improve the detection probability when to perform karyotype analysis. / Objectives: We conducted this study to externally validate EAU criteria and Ventimiglia nomogram and suggest modified nomogram for when to perform male karyotype analysis. / Materials and Methods: The subjects of this study were external cohort of 1,772 infertility patients who underwent karyotype analysis at CHA Fertility Center Seoul Station. Both male infertility patients who had abnormality on semen analysis and patients with recurrent abortion or recurrent implantation failure were included, and hormonal studies, scrotal sonography, and semen analysis were performed. . The area under receiver operating characteristics curve for diagnostic efficacy was used to investigate the value of each model. Multivariable logistic regression was performed to develop a new nomogram. / Results and Conclusion: Of the 1,772 patients, 1,505 patients underwent all tests necessary for analysis. Sixty six (4.3%) patients showed chromosomal abnormality. According to the EAU guideline, 272 (18.1%) patients should have undergone karyotype analysis, and 39 (14.3%) of whom had chromosomal abnormality. Sensitivity and specificity were 59.1% and 83.8% respectively, but 29 (43.9%) patients will not be properly diagnosed if patients are selected based on this guideline. The Ventimiglia nomogram’s AUC was 0.731 (p<0.001), and 349 (23.2%) patients would have been candidates for genetic workup, of which 43 (12.3%) patients would show chromosomal abnormality. Twenty-three (34.8%) patients still miss the opportunity to be diagnosed. According to our further evaluation, oligospermia was not significantly associated with chromosomal abnormality (r=0.017, p=0.506), while azoospermia showed strong correlation with chromosomal abnormality (r=0.266, p<0.001). Therefore, we modified the nomogram by replacing the sperm concentration with azoospermia, and the prediction rate was increased. With a 2% probability cut-off, the modified nomogram was able to screen 56 (84.8%) out of 66 genetic abnormalities. According to existing guidelines, diagnosis of a significant number of genetic abnormalities in male infertility patients may be missed. We modified existing nomogram, and we believe that this could be helpful to make decision when to perform karyotype analysis in infertile men.