Your kidneys filter waste, balance fluids, and regulate blood pressure — quietly, around the clock. Because early kidney disease often has no symptoms, blood and urine tests are the main way to catch problems before they advance.
The Core Kidney Tests
- Creatinine — a waste product from muscle. As kidney filtering declines, creatinine rises in the blood.
- BUN (Blood Urea Nitrogen) — reflects protein waste and hydration as well as kidney function.
- eGFR (estimated Glomerular Filtration Rate) — calculated from creatinine, age, and sex; it estimates how well your kidneys filter. An eGFR above 90 is ideal; below 60 for three months suggests chronic kidney disease.
- Urine Albumin (Microalbumin) / ACR — detects tiny amounts of protein leaking into urine, often the earliest sign of kidney stress.
What Abnormal Results Suggest
A high creatinine with a low eGFR points to reduced filtering capacity. The BUN-to-creatinine ratio helps distinguish dehydration from intrinsic kidney problems. A rising urine albumin is a red flag in people with diabetes or high blood pressure, the two leading causes of kidney disease worldwide.
Protecting Your Kidneys
- Keep blood pressure and blood sugar well controlled.
- Stay hydrated and limit excessive salt.
- Use painkillers like NSAIDs sparingly.
- Review your medications with your doctor, as some are cleared by the kidneys.
When to See a Doctor
An eGFR under 60, persistent protein in the urine, or a sudden rise in creatinine all warrant medical review. Caught early, kidney disease can often be slowed dramatically.
Understand Your Kidney Report
Upload your results to Lab Lens to see what your creatinine, BUN, and eGFR mean for your kidney health.