Renal function tests are medical assessments used to evaluate how well the kidneys are working. These tests measure substances in the blood, such as creatinine and urea, which indicate kidney health. A common test is the glomerular filtration rate (GFR), which estimates how effectively the kidneys filter waste from the blood. Additionally, urine tests can provide insights into kidney function by analyzing the presence of proteins, blood, or other substances. Abnormal results may suggest conditions like chronic kidney disease or acute kidney injury, prompting further investigation or treatment to protect kidney health.