Creatinine is a waste product in your blood. It comes from protein in your diet and the normal breakdown of muscles of your body. Creatinine is removed from blood by the kidneys and then passes out of the body in your urine. If you have kidney disease, the level of creatinine in your blood increases.
Blood (serum) and urine tests can check your creatinine levels. The tests are done to check how well your kidneys are working.
NIH: National Institute of Diabetes and Digestive and Kidney Diseases
- Creatinine (American Association for Clinical Chemistry)
- Creatinine - blood (Medical Encyclopedia) Also in Spanish
- Creatinine - urine (Medical Encyclopedia) Also in Spanish
- Creatinine clearance test (Medical Encyclopedia) Also in Spanish
- Microalbumin Creatinine Ratio (National Library of Medicine) Also in Spanish
- Urine Protein and Urine Protein to Creatinine Ratio (American Association for Clinical Chemistry)
- Urine Test: Microalbumin-to-Creatinine Ratio (For Parents) (Nemours Foundation) Also in Spanish
- ClinicalTrials.gov: Creatinine (National Institutes of Health)