**NOTE: All laboratory testing requires an authorizing physician in order to complete the laboratory testing**
A creatine kinase test may be used to detect swelling of muscles or serious muscle damage and/or to diagnose rhabdomyolysis if a person shows signs and symptoms, such as muscle weakness, muscle aches, and dark urine. The urine may appear to be dark in color because of a substance called myoglobin, which can cause damage to the kidneys. CK may be ordered by itself or paired with other blood chemistry tests such as electrolytes, BUN or creatinine. A urine myoglobin could be ordered as well.