I have had low alk phos. For the last 30 years my primary and GI Dr's do not seem to find a issue with it but I have had bone and joint problems and GI problems forever and while switching primary Dr's (mine retired) I was looking through my records and found I have had low alk phos. For 30 years. while looking I found their are problems with it being low and need to find the tests to find the cause