Further investigations are planned based on semen analysis results and findings from the clinical history. Firstly, it is important to evaluate the levels of essential hormones (FSH, LH, and total testosterone) related to the functioning of the male reproductive system and sperm production. Additional tests such as prolactin, estrogen, and thyroid hormones may also be requested based on physical examination and the patient's medical history. If azoospermia, a condition where no sperm is found in the semen, is detected, genetic investigations become highly important. These investigations typically include peripheral chromosome analysis (karyotyping) and Y chromosome microdeletion testing. If obstructive azoospermia is suspected, transrectal ultrasonography and some specific genetic tests should also be performed to assess the condition of the sperm ducts. In cases of non-obstructive azoospermia, Inhibin B level measurement can aid in diagnosis. All these tests are conducted to establish an accurate diagnosis and determine the appropriate treatment approach.