Creatinine, a muscle enzyme and a breakdown product of creatine, is produced by the liver, kidneys and pancreas from the amino acids glycine, arginine and methionine. Also naturally found in red meat and fish, creatinine helps the body to produce ATP (Adenosine triphosphate), the main source of usable cellular energy.
Significance of Creatinine
Creatinine is a waste product of normal muscle metabolism excreted by the kidneys into the urine and is one of the most important components of the blood test used in diagnosing chronic renal failure (CRF) in cats. If an elevated creatinine level occurs simultaneously with diluted urine, chances are good that your cat is suffering from CRF. Blood urea nitrogen (BUN) levels are checked along with creatinine levels to determine kidney function, but BUN levels are more susceptible to stress, diet and dehydration. Creatinine, less dependent than BUN on the cat's protein intake (the higher the protein, the higher the BUN level), is a more reliable indicator.
Normal Creatinine Levels
A normal creatinine ratio in cats ranges from 0.5 to 1.80 mg per decilitre. Higher creatinine levels may indicate that the kidneys are not properly filtering blood; however, higher levels are also found in heavily muscled cats simply because they have more muscle mass and are not cause for alarm.
Factors Affecting Creatinine Level
Your cat's creatinine level will be affected by diet if it regularly ingests foods containing high levels of creatine. Pancreatitis (inflammation of the pancreas) can also temporarily raise creatinine levels until the pancreatitis has successfully been treated. Autoimmune conditions, cancer, and congenital disorders will also raise creatinine, as, of course, will CRF.
Signs of High Creatinine Levels
Cats with elevated creatinine levels have been known to exhibit lethargy, pain during movement, appetite loss, seizures, vomiting and diarrhoea and are prone to both polydipsia (excessive drinking) and polyuria (excessive urination). Additional signs include an unkempt coat and limbs, and a swollen abdomen from fluid build-up.
Every cat has some level of creatinine in its system as a by-product of muscle metabolism. This level may be somewhat higher than normal if it consumes a diet composed largely of red meat and fish or is more muscular than the typical cat. However, elevated creatinine can also indicate the presence of diseases such as pancreatitis, CRF and certain autoimmune conditions, among others. It is crucial to consult your veterinarian as soon as possible if your cat exhibits any of the warning signs discussed above.