Urea Clinical Chemistry

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.

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.

Test Codes - Please visit www.nwlabs.co.uk or see our current price list for more information

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

Authors & References

NationWide Laboratories