Patients can test their estimated glomerular filtration rate by undergoing a glomerular filtration rate, or GFR, test, according to MedlinePlus. This test helps to determine if the kidneys are functioning properly. Typically, it estimates the amount of blood passing through the glomeruli each minute.
The GFR test requires a blood sample, which is sent to a lab to check the level of creatinine. The lab technician combines the level of creatinine in the blood sample with other factors to determine the glomerular filtration rate of a patient. Doctors use different formulas for children and adults when determining GFR. The formula may include age, ethnicity, gender, weight, height and blood creatinine measurement. A patient also undergoes the creatinine clearance test, which entails collecting urine for 24 hours to determine kidney function. However, this procedure is not always accurate.
To prepare for the test, a doctor recommends stopping any medications that may affect the results such as stomach acid medicines and antibiotics, notes MedlinePlus. A patient should inform the doctor about any current medications. Pregnant women should inform their doctor because gestation affects the test. Doctors recommend the GFR test for patients who suffer from kidney disease due to urinary blockage, hypertension, heart disease, diabetes and regular urinary tract infections.