All Kidney Health Biomarkers We Test

Carbon Dioxide (CO2)

Blood Urea Nitrogen (BUN)

Blood Urea Nitrogen (BUN) is the amount of nitrogen in your blood that comes from urea, the main waste product formed when your body breaks down protein. The liver (hepatocytes) converts ammonia—a toxic byproduct of protein metabolism—into urea via the urea cycle, making it safe to carry in the bloodstream. At home blood testing is available in select states. See FAQs below

BUN/Creatinine Ratio

The BUN/creatinine ratio is a comparison of two common blood wastes: urea nitrogen and creatinine. Urea nitrogen (BUN) comes from urea made in the liver as it detoxifies ammonia generated when proteins are broken down (urea cycle). Creatinine is formed at a steady rate as muscles use and renew creatine phosphate. At home blood testing is available in select states. See FAQs below

Calcium

Calcium blood testing measures the amount of calcium circulating in your bloodstream. Most of your body’s calcium is locked into bone and teeth as a hard mineral (hydroxyapatite). A small fraction travels in blood in two forms: free, biologically active calcium (ionized Ca2+) and calcium attached to proteins or small molecules (protein-bound and complexed). At home blood testing is available in select states. See FAQs below

Carbon Dioxide (CO2)

Carbon dioxide (CO2) blood testing reports the total CO2 in your blood, which mostly reflects bicarbonate, the body’s main base. In standard chemistry panels this “CO2” is predominantly bicarbonate (HCO3−), with small amounts of dissolved CO2 and carbonic acid (H2CO3). CO2 is made continuously as your cells burn carbohydrates and fats for energy. At home blood testing is available in select states. See FAQs below

Chloride

Chloride in blood is the chloride ion, a negatively charged electrolyte (anion) dissolved in the fluid outside your cells (extracellular fluid). It comes mainly from dietary salt (sodium chloride), is absorbed in the gut, and circulates in the bloodstream. The kidneys regulate chloride continuously, deciding how much to keep or excrete in response to hormones and the body’s acid–base needs. At home blood testing is available in select states. See FAQs below

Cockcroft-Gault Creatinine Clearance

Cockcroft-Gault creatinine clearance blood testing is a calculated estimate of how effectively your kidneys filter a muscle‑derived waste called creatinine out of the blood. Creatinine comes from normal muscle energy use (breakdown of creatine phosphate), enters the bloodstream at a fairly steady rate, and is removed by the kidney’s filtering units (glomeruli) into urine. At home blood testing is available in select states. See FAQs below

Creatinine

Creatinine is a small waste molecule made when your muscles use creatine for energy. It forms at a steady pace linked to muscle mass as creatine and phosphocreatine break down in skeletal muscle, then enters the bloodstream. The body doesn’t use creatinine; it is transported to the kidneys and eliminated in urine. At home blood testing is available in select states. See FAQs below

Estimated Glomerular Filtration Rate (eGFR)

Estimated glomerular filtration rate, or eGFR, is a calculated indicator of how much blood your kidneys filter each minute. It is not a substance in your blood but a number derived from a routine blood test. The calculation uses the level of creatinine (a waste product from muscle activity) and sometimes cystatin C (a small protein made by most cells), combined with your age and sex, to estimate the filtering work done by the kidney’s tiny sieves (glomeruli). At home blood testing is available in select states. See FAQs below

Potassium

Potassium Blood Testing measures the amount of potassium circulating in your blood (serum potassium, K+). Potassium is an essential mineral and electrolyte (a positively charged ion, or cation) that lives mainly inside your body’s cells. It enters the body from food, is absorbed in the gut, moves into and out of cells under hormonal signals (insulin, catecholamines), and is finely regulated by the kidneys under the influence of aldosterone. At home blood testing is available in select states. See FAQs below

Sodium

Blood sodium testing measures the amount of sodium, a charged mineral (electrolyte), in the liquid part of your blood. Sodium comes from your diet—mainly table salt (sodium chloride)—and after absorption in the gut it lives mostly in the fluid outside cells (extracellular fluid). At home blood testing is available in select states. See FAQs below