Overview
- Derived from breakdown of creatine in muscle.
- Excreted by kidneys.
- Not influenced by protein metabolism (unlike urea).
- Important marker of renal function; levels controlled by excretion rate.
Uses
In combination
- In combination with urea
and urine specific gravity as indicator of renal function.
Result data
Normal (reference) values
UK
- 40-130 žmol/l.
- 0.5-1.5 mg/dl.
- Conversion factor: mg/dl x 88.40 → umol/l.
- Interpret in conjunction with urine specific gravity.
- High levels are possible with decreased renal perfusion.
Abnormal values
Elevated
- Renal failure .
- Decreased renal perfusion (prerenal conditions).
- Acute renal failure. Also, increased phosphate and potassium .
- Chronic renal failure (also increased phosphates).
- Obstruction to urinary flow.
- Bladder rupture.
Errors and Artifacts
- False low with high bilirubin levels (unless dry reagent used).
- False elevation with ketones in ketoacidotic diabetes mellitus due to non-creatinine chromogens.
- Cephalosporins interfere with analytical method, giving false low level.
Sources
Publications
Other sources of information
- Ettinger S J & Feldman E C (eds) (2000) Textbook of Veterinary Internal Medicine. 5th edn. Philadelphia: W B Saunders & Co.
- Kaneko J J, Harvey J W & Brass M L (eds) (1997) Clinical Biochemistry of Domestic Animals. 5th edn. Boston: Academic Press.
- Duncan J R, Prasse K W & Mahaffey E A (1994) Veterinary Laboratory Medicine. Clinical Pathology. 3rd edn. Iowa: Iowa University Press.
