Alkaline phosphatase may be increased in the CSF of patients with intracranial germ cell tumors. When increased, isoenzyme testing can identify if a heat-stable isoenzyme (ie, germ cell or placental) is present but cannot quantify the amount of activity.
Freeze within two (2) hours of sample collection
Frozen (preferred) – 1 year
Refrigerate – 1 week
Ambient – NO
Quantitative Heat Inactivation/Enzymatic
Total alkaline phosphatase: 0 - 1 U/L