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Urea is principally a product of amino acid deamination in the liver. Urea is primarily excreted by the kidneys and is the most commonly used test of renal function with creatinine. References: [[NationWide Laboratories]]
−== Small Animals ==
−=== Increased urea, renal azotaemia ===
−* Acute renal failure
−* Chronic renal failure
−=== Increased urea, prerenal azotaemia ===
−* Dehydration
−* Shock
−* High protein diet
−* Fever
−* Reduced cardiac output
−* Hyperthyroidism
−* Hypoadrenocorticism
−* Gastrointestinal haemorrhage
−=== Increased urea, postrenal azotaemia ===
−* Feline urological syndrome
−* Bladder rupture
−* Calculi
−* Neoplasia
−* Perineal herniation
−=== Causes of a low urea concentration ===
−* Polydipsia/polyuria (due to causes other than renal disease)
−* Hepatic insufficiency, especially portosystemic shunt
−* Low protein diet
−* Late pregnancy
−* Anabolic steroids
−=== Complementary tests ===
−Creatinine and phosphorus. Urine specific gravity, urinalysis, glomerular filtration rate and SDMA.
−== Equine ==
−=== Increased urea, prerenal azotaemia ===
−* Dehydration
−* Reduced renal perfusion
−* Congestive heart failure
−* Excessive muscle catabolism
−* High protein diet
−* Grass sickness
−=== Increased urea, renal azotaemia ===
−* Acute renal failure
−* Chronic renal failure
−=== Increased urea, postrenal azotaemia ===
−* Obstruction, ruptured bladder
−* Ruptured bladder in neonatal foals
−* Low urea concentrations
−* Hepatic insufficiency
−* Young foals (normal by 60 days)
−=== Complementary tests ===
−Creatinine and phosphorus. Urine specific gravity (<1.020 in a dehydrated or azotaemic horse suggests renal tubular dysfunction). Urine clearance or fractional electrolyte excretion ratios (renal
−tubular dysfunction).
−Test Codes - Please visit www.nwlabs.co.uk or see our current price list for more information
−== References ==
−Text referenced 'Nationwide Laboratories' [[NationWide Laboratories]]
−Small Animals: [[NationWide Laboratories]]
−Equine: [[NationWide Laboratories]]
[[File:NationWide Logo.jpeg|right|link=https://www.nwlabs.co.uk/|alt=NationWide Logo|240x240px|In Partnership with NationWide Laboratories|frameless|thumb|]]
==Description==
==Description==
Urea is a form of nitrogenous waste formed from [[Ammonia|ammonia]] via the urea cycle in the liver. It freely crosses lipid membranes and is filtered into the glomerular filtrate in the renal glomerulus. A proportion of this filtered urea is reabsorbed passively before final excretion and it forms a vital of the concentration gradient needed to prevent passive diuresis.
Urea is a form of nitrogenous waste formed from [[Ammonia|ammonia]] via the urea cycle in the liver. It freely crosses lipid membranes and is filtered into the glomerular filtrate in the renal glomerulus. A proportion of this filtered urea is reabsorbed passively before final excretion and it forms a vital of the concentration gradient needed to prevent passive diuresis.
−==Clinical Significance==
==Clinical Significance==
An increase in serum concentrations of urea and creatinine is known as '''[[Azotaemia|azotaemia]]''' and it is found almost exclusively in animals with kidney disease.
An increase in serum concentrations of urea and creatinine is known as '''[[Azotaemia|azotaemia]]''' and it is found almost exclusively in animals with kidney disease.
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*A diet with a low protein content or malnutrition.
*A diet with a low protein content or malnutrition.
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−[[Category:Blood Biochemistry Changes]][[Category:To_Do_-_Blood]]
[[Category:Blood Biochemistry Changes]][[Category:To_Do_-_Blood]]