text_1: Last week I had a 72-year-old man with an elevated alkaline phosphatase of approximately 210 units per liter (normal 20 - 125).  I broke it down, but each individual component was normal:  bone approximately 40% (normal 23 to 62%), liver approximately 55% (normal 38 to 72%), and intestinal approximately 5% (normal less than 18%).
text_2: How should you work up an elevated alkaline phosphatase when the proportions of each component are normal?