When to perform karyotype analysis in infertile men? Validation of the European Association of Urology guidelines with the proposal of a new predictive model

Known genetic alterations play a major role in perturbing male reproductive health. We sought to retrospectively validate the European Association of Urology (EAU) guidelines for karyotype analysis (KA) in a homogenous cohort of 1168 White European men presenting for primary couple's infertility (noninterracial infertile couples only) and to develop a novel nomogram capable of predicting karyotype alterations. Overall, 742 (63.5%) patients would have deserved KA according to the EAU guidelines. Of those, 48 (6.9% of the assessable patients according to EAU guidelines) displayed any kind of alteration at KA. Conversely, hypothetically relying on the EAU criteria, 12 (20%) out of 60 patients with karyotype abnormalities would not have been candidates for the same genetic assessment. Overall, 694 (62.6%) patients would have been candidates for genetic workup despite having a normal karyotype. As a whole, the EAU guideline sensitivity, specificity, and discrimination were 80%, 37%, and 59%, respectively. We developed a novel nomogram, with a 2% probability cut-off, which allows for a more careful detection of KA alterations. Patient summary The application of the European Association of Urology guidelines for karyotype analysis does not ensure an adequate diagnostic process. In this regard, we propose a novel diagnostic tool to improve detection of alterations at karyotype analysis.