EGFR stands for estimated glomerular filtration rate. It is an estimation determined by blood testing for creatinine that is used to determine how well a patient's kidneys are working.
Creatinine is waste that comes from the muscles, and a healthy Kidney works to filter creatinine from the blood. This information, combined with age, sex and race, is used to determine a person's EGFR. A normal EGFR typically rests around 60 or more, and anything lower than that might point to kidney disease.
EGFR tests are often ordered when certain symptoms of Kidney disease occur. These symptoms include high blood pressure, mid-back pain, burning sensations or abnormal discharges during urination, decrease in urine level, foamy or coffee-colored urine, puffiness around the face or legs, tiredness, loss of concentration, itchiness, darkened skin, muscle cramps, loss of appetite, nausea or vomiting, and numbness in hands or feet. EGFR tests detect kidney disease more reliably than creatinine tests alone and are usually ordered alongside creatinine tests at no additional cost. A person's EGFR may increase with age and may be inaccurate if a subject is under 18, pregnant, very overweight or extremely muscular. An EGFR may be affected by a variety of drugs, such as gentamicin, cisplatin and cefoxitin.