normal levels:

• normal persons
• neurogenic atrophies¹

decreased levels:

• persons with unusually low muscle mass

increased levels:

• skeletal muscle conditions:
  1. progressive (Duchenne) muscular dystrophy
  2. dermatomyositis or polymyositis
  3. limb-girdle dystrophy
  4. myotonia dystrophy
  5. rhabdomyolysis from any etiology...probably even critical illness myopathy.
• liver disease :
  1. any type of hepatic necrosis (in acute viral hepatitis, tends to parallel SGPT¹)
  2. hepatotoxic liver injury or necrosis
  3. carcinomatous metastasis to liver¹
• other:
  1. acute myocardial infarction¹
  2. acute pancreatitis¹
  3. prostatic tumors¹
  4. other neoplasms¹
  5. delirium tremens¹
  6. intra-muscular injection of medications¹

1. A B C's of Interpretive Laboratory Data, Seymour Bakerman, M. D., PhD., 1984.