1. Artifactual as a result of hypoalbuminemia
  2. Acute pancreatitis
  3. Surgically induced hypoparathyroidism (transient or permanent)
  4. Necrotizing fasciitis
  5. Inadequate intestinal absorption
  6. Excessive fluid losses from pancreatic or intestinal fistulae
  7. Chronic diarrhea
  8. Renal insufficiency with impaired calcium resorption
  9. Hypomagnesemia
  10. Hyperphosphatemia