Creatine kinase, also called creatine phosphokinase, is an enzyme that breaks down muscle cells for energy to stimulate growth and muscle contractions. CK is found primarily in your skeletal muscles, heart, brain and lung tissues. Creatine kinase seeps into your circulation in response to muscle exercise, injury or damage, and is measured with blood testing. Creatine kinase breaks down into creatinine, a waste product, which is filtered through your kidneys and excreted in urine.
Creatine Kinase Forms
Creatine kinase has three different forms, called isoenzymes, that are invaluable when identifying your specific tissue damaged, according to the University of Maryland Medical Center. CK-BB shows brain tissue damage, such as brain cancer. CK-MB reflects heart muscle injury, as in a heart attack. CK-MM demonstrates damage to skeletal muscle, like strenuous exercise or muscular dystrophy. Further testing with evaluation of signs and symptoms are necessary for a definitive diagnosis.
Kidney Function
The kidneys' responsibilities include elimination of waste products, stabilizing fluids, controlling your blood pressure and regulating red blood cell formation. When your kidney function is decreased, waste products like creatinine increase in the blood, according to the National Kidney Foundation. Kidney disease, most often caused by uncontrolled diabetes and high blood pressure, frequently has no symptoms with initial stages. As your kidney function deteriorates, signs and symptoms like nausea, vomiting, anemia and increased creatinine appear.
Creatinine Connection
Creatinine, the waste product of creatine kinase, has an important role in evaluating kidney disease. Normal kidneys filter creatinine and excrete it in the urine at a stable level on a daily basis. As your kidney function decreases, creatinine begins to increase in the blood, according to Lab Tests Online. The increased levels may reflect an acute kidney injury, kidney infections, diabetes problems or kidney obstructions. Additional lab tests may also reveal kidney malfunction.
Kidney Failure
The inability of your kidneys to perform necessary functions, such as filtration, leads to kidney failure that may be acute or chronic. Acute kidney failure occurs quickly with a decrease in blood flow to your kidneys and a rapid increase of waste products such as creatinine. Chronic kidney disease occurs with a progressive decline in function with a corresponding increase in waste products. Measurement of creatinine, along with other lab tests, monitors kidney disease status.
