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FIB 4 index Explanation and Clinical Context The FIB 4 index is a noninvasive score that estimates the probability of advanced liver fibrosis using routinely available values including patient age AST ALT and platelet count. It is calculated as age in years multiplied by AST in U per L divided by platelet count in 10 to the power of 9 per L times the square root of ALT in U per L. Commonly used cutoffs are less than
Explanation and Clinical Context The Fick principle is one of the most fundamental physiological methods used to determine cardiac output. This calculation is based on the relationship between oxygen consumption and the arteriovenous oxygen content difference. The method assumes that the uptake or release of oxygen by the tissues is equal to the product of blood flow and the arteriovenous oxygen difference. In clinic
Explanation and Clinical Context Fluid maintenance requirement determines the physiological daily fluid needs for patients considering metabolic water losses. Clinicians commonly use the four two one formula where the first ten kilogram of body weight receives four mL per kg per hour the next ten kilogram receives two mL per kg per hour and the remaining weight receives one mL per kg per hour. This formula assists in
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