This category brings together articles on laboratory investigations performed on urine samples. Each article explains why the test is ordered, what it measures, how to collect the sample properly, and how results are interpreted. Topics include routine urine examination, urine culture, 24-hour urine protein, microalbumin, ketones, glucose, and specialized metabolic studies. With clear explanations of reference ranges and abnormal findings, these guides help patients, students, and healthcare professionals understand the clinical value of urine testing in detecting kidney disease, infections, diabetes complications, and metabolic disorders.