Creatinine Blood Test with eGFR

This test measures creatinine in your serum and reports an eGFR (estimated glomerular filtration rate), both listed on Quest's directory for this code. eGFR is calculated from creatinine, age and sex and is expressed in mL/min/1.73 m², an estimate of how much blood the kidneys filter each minute, adjusted to an average body size. Your clinician reads the two numbers together.

Adults who want to check or follow kidney function: people with diabetes, high blood pressure, heart disease, obesity, or a family history of kidney disease; people over 50 or who smoke; people taking medicines that can affect the kidneys; and anyone re-checking a creatinine or eGFR that came back outside the expected range on a previous panel.

Any time of day; no fasting is needed. For monitoring, testing at a similar time and in similar conditions each time (normally hydrated, no heavy workout the day before) makes results easier to compare. Because one abnormal value cannot diagnose kidney disease, clinicians usually repeat creatinine and eGFR before drawing conclusions.

Your report shows creatinine with an age- and sex-specific reference range and your eGFR. Quest's reference range for eGFR is 60 mL/min/1.73 m² or higher. A creatinine above the range or an eGFR below 60 can point to reduced kidney filtering from kidney disease, poor blood flow to the kidneys (for example dehydration or heart failure) or a urinary blockage, but it can also reflect dehydration, high muscle mass, intense exercise or a meat-heavy meal. Chronic kidney disease is defined by an eGFR below 60 lasting more than 3 months (or kidney damage such as albumin in the urine), so a single low result is usually repeated and often paired with a urine albumin test or a cystatin C test. Low creatinine is uncommon and may reflect low muscle mass, malnutrition or serious liver disease. A normal result does not fully rule out early kidney damage. JustLabs results are informational; review them with a clinician.