A CK-MB test may be used as a follow-up test to an elevated CK in order to determine whether the increase is due to heart damage or skeletal muscle damage. The test is most likely to be ordered if a person has chest pain or if a person's diagnosis is unclear, such as if a person has nonspecific symptoms like shortness of breath, extreme fatigue, dizziness, or nausea. CK and CK-MB were once the primary tests ordered to detect and monitor heart attacks, but they have now been largely replaced by the troponin test, which is more specific for damage to the heart.