Kidney Function Tests are medical assessments that evaluate how well the kidneys are working. These tests measure substances in the blood and urine, such as creatinine and urea, which help determine the kidneys' ability to filter waste. Common tests include the glomerular filtration rate (GFR), which estimates how much blood passes through the kidneys each minute, and urine tests that check for protein or blood. Abnormal results may indicate kidney disease or other health issues, prompting further investigation or treatment.