Kidney Lab Test Directory
Clear, patient-centered guides to 20 essential blood and urine tests doctors use to evaluate kidney function, detect early damage, and monitor chronic kidney disease.
Serum Creatinine
Creatinine is a natural waste byproduct generated by routine muscle movement. Healthy kidneys filter it continuously out of the bloodstream and excrete it in urine.
Estimated Glomerular Filtration Rate (eGFR)
eGFR shows how many milliliters of blood plasma your kidneys clean each minute. It is the gold-standard number doctors use to determine kidney health and stage chronic kidney disease.
Blood Urea Nitrogen (BUN)
BUN measures urea nitrogen in your blood, a waste byproduct created when your liver breaks down protein. Your kidneys normally filter urea out through urine.
BUN-to-Creatinine Ratio
This ratio compares your blood urea nitrogen against your serum creatinine. It helps clinicians distinguish whether kidney trouble stems from dehydration, blood flow issues, or intrinsic kidney damage.
Urine Albumin-to-Creatinine Ratio (UACR)
UACR is a urine test that checks for microscopic amounts of protein (albumin) leaking past kidney filters. It is the single earliest warning sign of kidney damage.
Serum Potassium (K+)
Potassium is an essential mineral and electrolyte that controls nerve signals and regulates the electrical rhythm of your heartbeat. Healthy kidneys remove excess potassium daily.
Serum Phosphorus (Phosphate)
Phosphorus works with calcium to build and maintain strong bones. When kidney function declines, excess phosphorus builds up in the blood and can pull calcium out of bones.
Serum Calcium (Ca2+)
Calcium is critical for muscle contraction, heart rhythms, and bone strength. In kidney disease, calcium balance is closely tied to vitamin D and phosphorus.
Serum Sodium (Na+)
Serum sodium is the primary electrolyte that maintains fluid balance and blood pressure. In kidney disease, low sodium often reflects fluid retention rather than a lack of salt.
Serum Albumin (Blood)
Serum albumin is the main protein in your blood, produced by the liver. It keeps fluid from leaking out of blood vessels and reflects your overall nutritional health.
Hemoglobin & Hematocrit (Renal Anemia)
Hemoglobin is the iron-rich protein in red blood cells that carries oxygen to your brain, heart, and muscles. Failing kidneys produce less erythropoietin (EPO), leading to renal anemia.
Carbon Dioxide / Bicarbonate (CO2 / HCO3)
Carbon dioxide on a metabolic panel measures bicarbonate, your body's main chemical buffer against acid. Impaired kidneys struggle to excrete daily acids, causing metabolic acidosis.
Serum Cystatin C & eGFR-cys
Cystatin C is a filtration marker produced by all cells in the body at a steady rate. Unlike creatinine, it is not affected by muscle mass, diet, or age, making it the premier confirmatory test for kidney function.
Intact Parathyroid Hormone (iPTH)
iPTH regulates calcium and phosphorus balance. In kidney disease, parathyroid glands produce excessive PTH to compensate for failing mineral clearance, leading to renal bone disease.
25-Hydroxy Vitamin D (Calcidiol)
25-Hydroxy Vitamin D reflects your total body vitamin D stores. Healthy kidneys convert it into calcitriol, the active hormone that controls calcium absorption and suppresses excess parathyroid hormone.
Ferritin & Transferrin Saturation (Iron Panel / TSAT)
Ferritin measures your total stored iron, while TSAT shows how much iron is available in your bloodstream to make red blood cells. Both are essential to manage renal anemia.
Urine Protein-to-Creatinine Ratio (UPCR)
While UACR checks specifically for albumin, UPCR measures all proteins leaking into urine (including tubular proteins and immunoglobulins). It is essential for diagnosing complex kidney conditions.
Serum Magnesium (Mg2+)
Magnesium is a vital mineral that regulates muscle contractions, nerve transmission, and vascular calcification. Both high and low levels require careful management in kidney disease.
Serum Uric Acid (Urate)
Uric acid is a waste product formed from the breakdown of purines in food and body cells. Healthy kidneys excrete two-thirds of uric acid daily; reduced clearance triggers painful gout attacks and uric acid stones.
Hemoglobin A1c (in Kidney Disease)
Hemoglobin A1c reflects your average blood sugar over the past 2-3 months. In kidney disease, shortened red blood cell lifespans and anemia can cause falsely low readings that mask high blood glucose.