Search results
Results From The WOW.Com Content Network
The fractional excretion of sodium (FE Na) is the percentage of the sodium filtered by the kidney which is excreted in the urine. It is measured in terms of plasma and urine sodium , rather than by the interpretation of urinary sodium concentration alone, as urinary sodium concentrations can vary with water reabsorption .
Urine electrolyte levels can be measured in a medical laboratory for diagnostic purposes. The urine concentrations of sodium , chlorine and potassium may be used to investigate conditions such as abnormal blood electrolyte levels, acute kidney injury , metabolic alkalosis and hypovolemia .
The urine sodium is expressed as a concentration (such as millimoles per liter). The result must therefore be interpreted in the context of the degree of urine concentration present. Alternatively, the urine sodium can be standardized to the excretion of creatinine using a formula such as the fractional excretion of sodium (FENa).
It uses Na-H antiport, Na-glucose symport, sodium ion channels (minor). [1] It is stimulated by angiotensin II and aldosterone, and inhibited by atrial natriuretic peptide. It is very efficient, since more than 25,000 mmol/day of sodium is filtered into the nephron, but only ~100 mmol/day, or less than 0.4% remains in the final urine.
Therefore, creatinine concentrations in blood and urine may be used to calculate the creatinine clearance (CrCl), which correlates approximately with the glomerular filtration rate (GFR). Blood creatinine concentrations may also be used alone to calculate the estimated GFR (eGFR). The GFR is clinically important as a measurement of kidney function.
Example of a container used for collecting 24-hour urine samples. This particular container is free of trace metals to allow for accurate measurement of these substances in urine. The techniques used to collect urine specimens vary based on the desired test. A random urine, meaning a specimen that is collected at any time, can be used for many ...
A simple means of estimating renal function is to measure pH, blood urea nitrogen, creatinine, and basic electrolytes (including sodium, potassium, chloride, and bicarbonate). As the kidney is the most important organ in controlling these values, any derangement in these values could suggest renal impairment.
The renal clearance ratio or fractional excretion is a relative measure of the speed at which a constituent of urine passes through the kidneys. [ 1 ] [ 2 ] It is defined by following equation: c l e a r a n c e r a t i o o f X = C x C i n {\displaystyle clearance\ ratio\ of\ X={\frac {C_{x}}{C_{in}}}}