1,329 calculators and references across 60 specialties, with formula confidence shown up front.
Explanation and Clinical Context The CKD EPI GFR equation provides an estimation of glomerular filtration rate which is a fundamental indicator of kidney function. This equation improves accuracy especially in higher GFR ranges and reduces the systematic bias found in previous formulas. The calculation incorporates serum creatinine age sex and race to generate a clinically relevant estimate of renal function. An esti
Cockcroft Gault creatinine clearance estimation Explanation and clinical context The Cockcroft Gault equation provides an estimate of creatinine clearance in milliliters per minute using patient age weight serum creatinine and sex. The formula is CrCl equals open parentheses 140 minus age close parentheses times weight divided by open parentheses 72 times serum creatinine close parentheses. For female patients multip
Dialysis Adequacy and Dose Index Explanation and Clinical Context Dialysis adequacy is commonly quantified using two complementary measures. The urea reduction ratio is the percent reduction in blood urea concentration during a single hemodialysis session and offers a simple quality control metric. Single pool KtV from the Daugirdas second generation formula provides an estimate of dialysis dose accounting for treatm
Explanation and Clinical Context The European Kidney Function Consortium equation is a contemporary and validated approach for estimating glomerular filtration rate across broad age ranges. The equation improves accuracy by using a population based reference serum creatinine distribution that reduces bias commonly seen in previous formulas. It is applicable to adult and adolescent patients and provides an estimation
Fractional Excretion of Sodium FeNa Explanation and Clinical Context Fractional excretion of sodium FeNa quantifies the percentage of filtered sodium that is ultimately excreted in urine using simultaneously obtained urine and plasma measurements. The formula is FeNa equals Una times Pcr divided by Pna times Ucr all multiplied by one hundred to yield a percentage. FeNa is commonly used to help distinguish reduced ren
Fractional Excretion of Urea FeUrea Explanation and Clinical Context Fractional Excretion of Urea FeUrea estimates the percentage of filtered urea that is excreted in urine. The calculation uses urine urea concentration serum urea concentration urine creatinine concentration and serum creatinine concentration. The formula is FeUrea equals Uurea times Scr divided by Surea times Ucr multiplied by 100 percent. FeUrea co
Jelliffe renal function equation Explanation and clinical context The Jelliffe equation estimates creatinine clearance in adults from age 20 to 80 years by combining an age dependent production term with measured serum creatinine and body surface area. The equation adjusts for sex by applying a ten percent reduction for female sex to reflect lower creatinine production. In this implementation serum creatinine may be
Decision guide and clinical suggestions The STONE score is a clinical prediction rule to estimate probability of uncomplicated ureteral stone based on five clinical items. The original computed score ranges from 0 to 13. The modified score excludes the origin component and ranges from 0 to 10. For an original STONE score in the high probability range ten to thirteen and for a modified STONE score in the high range ni
Explanation and Clinical Context The MDRD equation used here is the original four variable model intended to estimate glomerular filtration rate adjusted to a body surface area of 1.73 square meters. The equation requires serum creatinine in mg per dL age in years sex and an indicator for black ethnicity. The formula is eGFR equals 186 times serum creatinine to the power of minus 1.154 times age to the power of minus
Protein Creatinine Ratio Explanation and Clinical Context The protein creatinine ratio is an accepted method to estimate daily urinary protein excretion without the need for a full twenty four hour urine collection. It provides a reliable assessment of proteinuria by comparing the concentration of urine protein to urine creatinine in a single spot sample. The ratio correlates closely with total daily protein excretio
Renal Failure Index Explanation and Clinical Context Renal Failure Index is a calculated parameter used to differentiate prerenal azotemia from intrinsic renal tubular injury. It incorporates urine sodium urine creatinine and plasma creatinine into a single ratio that reflects tubular sodium handling. A low value reflects preserved tubular sodium conservation which often indicates prerenal physiology. A higher value
Sodium Na mEqL Glucose mgdL BUN mgdL Explanation and Clinical Context Serum osmolality reflects the concentration of dissolved particles in plasma and provides an essential window into the body water balance. The major contributors to serum osmolality are sodium glucose and blood urea nitrogen which form the basis of the widely used calculated osmolality formula. Normal serum osmolality ranges from two hundred sevent
Urine Potassium Plasma Potassium Urine Osmolality Plasma Osmolality Transtubular Potassium Gradient TTKG Explanation and Clinical Context TTKG is a physiologic estimate of potassium secretion in the cortical collecting duct and reflects the activity of aldosterone as well as distal tubular sodium delivery. It is calculated by the ratio of urine potassium concentration to plasma potassium concentration multiplied by t
Urea Reduction Ratio URR Explanation and Clinical Context Urea Reduction Ratio is a standard measure of the adequacy of hemodialysis based on the reduction of blood urea nitrogen concentration before and after a dialysis session. URR reflects how effectively solute clearance is achieved during treatment. A higher URR indicates better dialysis efficiency. A value of sixty five percent or higher is generally accepted a
Urine Sodium Na Urine Potassium K Urine Chloride Cl Urine Anion Gap Explanation and Clinical Context The urine anion gap is a practical bedside calculation that estimates urinary ammonium excretion. It is calculated using the sum of urine sodium and urine potassium minus urine chloride. Ammonium is excreted in association with chloride therefore low chloride relative to sodium and potassium suggests impaired ammonium
Wright equation for estimated glomerular filtration rate explanation and clinical context The Wright equation estimates glomerular filtration rate in milliliters per minute using patient age weight height sex serum creatinine and body surface area computed by the DuBois formula. The equation was derived to improve accuracy of estimation in older adults and in oncology patients and incorporates an age dependent consta