|See Also||Lab Tests|
Creatinine is commonly used as a measurement of kidney function. Creatinine is a waste product produced by muscles due to the breakdown of a compound called creatine phosphate. Creatine phosphate is a storage depot for muscle energy and is produced primarily from the contraction of muscle. The production of creatine phosphate is dependent on the muscle mass of the person, and is removed from the body by the kidneys.,
- Serum creatinine levels can be affected by the muscle mass of the individual.
- Patients with increased muscle mass may therefore have slightly higher creatinine levels than patients with decreased muscle mass (older adults and children).
- Creatinine is often used with BUN to assess impaired kidney function and is considered to be a more specific and sensitive test indicator of renal disease than BUN.
- No fasting is required.
- Factors which can cause increased levels
- Factors which can cause decreased levels
- Drugs: Cephalosporin antibiotics, histidine, and quinidine compounds
Ranges: The following are the reference ranges for this lab. However, lab ranges can vary by laboratory and country. 
|Standard U.S. Units||Standard International Units|
|Conventional Laboratory Range||0.6-1.5 mg/dL||53.0-132.6 umol/L|
|Optimal Range||0.8-1.1 mg/dL||70.7-97.2 umol/L|
|Alarm Ranges||> 1.6 mg/dL||> 141.4 umol/L|
High levels indicate:
- Urinary tract congestion or obstruction (uterine hypertrophy, Uterine inflammation, UTI)
- Drug causes: Aspirin/NSAIDS, Antibiotics, Bismuth, Lithium, Indomethacin, Diuretics (Furosamide, thiazide, etc.)
- Other conditions: Urinary tract obstruction, dehydration, creatine supplementation, uncontrolled diabetes, congestive heart failure
Low levels indicate:
- Muscle atrophy/ or nerve-muscle degeneration
- Other conditions: Little metabolism in the muscles indicating a need for exercise, liver disease, muscular dystrophy, multiple sclerosis
- Sedentary lifestyle
- Malnutrition / debility
- Pagana Kathleen D, Pagana Timothy J, (1998) Mosby's Manual of Diagnostic and Laboratory Tests, Mosby, Inc
- Weatherby Dicken, Ferguson Scott (2002) Blood Chemistry and CBC Analysis: Clinical Laboratory Testing from a Functional Perspective, Bear Mountain