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How eGFR estimates kidney filtration from creatinine and age, what values indicate at each stage, and why tracking changes matters.
What creatinine measures, why muscle mass and supplements can shift it, and how to read it alongside eGFR and cystatin C.
What SDMA measures, how it differs from creatinine, and what elevated levels mean for kidney and vascular health.
What the Cockcroft-Gault creatinine clearance estimate measures, how to read high and low values, and which companion tests complete the kidney picture.
What the BUN/creatinine ratio measures, why urea and creatinine respond differently to dehydration, and how to read your result.
Understand why uric acid matters beyond gout for metabolic health.
What cystatin C measures, why it outperforms creatinine in certain populations, the thyroid confounder, and how to read your eGFR result.
What BUN measures, how to interpret the BUN-to-creatinine ratio, and which companion tests reveal true kidney filtration.
Explore how ADMA affects nitric oxide production, blood vessel function, and cardiovascular risk. Learn which companion markers clarify the vascular risk picture.
Urine specific gravity is a measure of the concentration of solutes in your urine, reflecting the kidney's ability to concentrate or dilute urine in response to the body's hydration needs. A high specific gravity indicates that urine is more concentrated than normal, which may result from dehydration, excess solute intake, or certain medical conditions. Monitoring this value can provide useful insight into hydration status and kidney function.
Hyaline casts are translucent, cylindrical structures formed in the kidney tubules from Tamm-Horsfall protein, a glycoprotein naturally secreted by tubular cells. Small numbers of hyaline casts can appear in healthy individuals, particularly after vigorous exercise or dehydration. However, persistently elevated levels may suggest underlying kidney stress and are worth discussing with a healthcare provider.
Urine specific gravity measures the concentration of dissolved solutes in your urine relative to pure water, reflecting how well your kidneys dilute or concentrate waste products. A low specific gravity reading suggests that urine is more dilute than expected, which may relate to fluid intake, kidney tubular function, or hormonal signaling. Monitoring this marker can offer meaningful insight into hydration status, renal concentrating ability, and overall metabolic balance.
Collecting a urine sample during menstruation can introduce menstrual blood into the specimen, potentially affecting test accuracy. Understanding proper collection techniques helps ensure reliable results and may prevent the need for repeat testing. A clean-catch method and appropriate timing are key considerations for anyone who needs a urinalysis while on their period.
Erythrocytes in urine, also known as hematuria, refers to the presence of red blood cells in a urine sample. While sometimes caused by benign factors such as vigorous exercise or menstrual contamination, it can also signal conditions affecting the kidneys, bladder, or urinary tract. A urinalysis that detects erythrocytes is an important screening tool that helps guide further evaluation when needed.
Urine pH is a measure of how acidic or alkaline your urine is, and it can reflect dietary patterns, hydration status, and metabolic processes. While urine pH naturally fluctuates throughout the day, consistently high (alkaline) readings may be associated with certain infections, kidney conditions, or dietary factors. Understanding what influences urine pH can help you have more informed conversations with your healthcare provider.
Uric acid blood testing measures urate, the end product of purine breakdown. Purines come from the nucleic acids in your cells and from food. As cells turn over and purines are recycled or degraded, enzymes convert them through hypoxanthine and xanthine to uric acid (urate), mainly via xanthine oxidase in the liver and intestinal tissues. Available at 2,000+ lab locations and at-home (select states). See FAQs below
SDMA blood testing measures symmetric dimethylarginine, a small amino acid derivative that appears when cells break down methyl-marked proteins. Inside the nucleus, enzymes add methyl groups to arginine residues on proteins (protein arginine methylation). When those proteins are recycled, the modified arginine is released as SDMA and enters the bloodstream. Available at 2,000+ lab locations and at-home (select states). See FAQs below
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). Available at 2,000+ lab locations and at-home (select states). See FAQs below
Cystatin C is a small protein that all your body’s cells release into the bloodstream at a steady rate (cysteine protease inhibitor made by nucleated cells). The kidneys filter it out through the glomeruli, and the filtered protein is then taken up and broken down by the tubules, so it doesn’t return to the blood. Available at 2,000+ lab locations and at-home (select states). See FAQs below
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. Available at 2,000+ lab locations and at-home (select states). See FAQs below
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. Available at 2,000+ lab locations and at-home (select states). See FAQs below
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. Available at 2,000+ lab locations and at-home (select states). See FAQs below
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. Available at 2,000+ lab locations and at-home (select states). See FAQs below
Asymmetric dimethylarginine (ADMA) is a small molecule made when the body modifies certain proteins during normal cell activity. Enzymes add methyl groups to arginine side chains in proteins (protein arginine methyltransferases, PRMTs). When those proteins are broken down, free ADMA is released into the bloodstream. Available at 2,000+ lab locations and at-home (select states). See FAQs below
Blood testing clarifies nephrotic syndrome’s protein loss and lipid shifts, guiding diagnosis and monitoring. At Superpower, we measure albumin, total protein, LDL, triglycerides, and ApoB. We offer in-clinic and at-home testing; home kits are currently available in selected states. (See FAQs below for more info).
Measuring uric acid in blood detects excess levels early, signaling risk for gout, kidney stones, and cardiometabolic strain (hyperuricemia). At Superpower, we offer uric acid testing for Hyperuricemia—available in-clinic and at home. Home blood testing is currently offered in selected states. (See FAQs below for more info).
Blood testing clarifies gout risk by quantifying uric acid burden and its cardiometabolic context. At Superpower, we measure uric acid and the uric acid/HDL ratio. We offer in-clinic and at-home testing; home gout testing is currently available in selected states. (See FAQs below for more info).
Blood testing detects kidney dysfunction early. Superpower provides tests for creatinine, eGFR, BUN, albumin, corrected calcium, and potassium to evaluate filtration, protein balance, and electrolyte-mineral control. Superpower offers in-clinic and at-home testing; home blood testing for chronic kidney disease is available in selected states. (See FAQs below for more info).
Early blood testing for acute kidney injury identifies declining filtration before symptoms, protecting whole‑body balance. Superpower offers creatinine, eGFR, BUN, and BUN/creatinine ratio testing. Access in‑clinic or at‑home options; home collection for AKI testing is available in selected states. (See FAQs below for more info).