Creatinine

A breakdown product of creatine phosphate in muscle and excreted in urine, mainly by simple glomerular filtration without much active secretion or reabsorption. Increased serum concentrations indicate decreased glomerular filtration which might reflect hypovolaemia and/or acute or chronic renal injury. Discovery of high serum creatinine requires urgent fluid therapy and diuresis to attempt to reverse/prevent further irreversible renal injury. Ideally creatinine should return to the normal range after fluid therapy although horses that stabilise under 250-300 mol/L tend to do reasonably well. Occasionally low serum concentrations are seen in horses with hepatic insufficiency. In a well hydrated horse without renal disease, creatinine can be used as a marker of simple glomerular filtration and used for comparison with other urinary analytes to give an indication of relative secretion/reabsorption (e.g. electrolytes) or as a marker of urine concentration (e.g. GGT).

See Also

• Urea
• SDMA