I am IBS-C and interested in knowing how to test for levels of Calcium,Vitamin A and D. Is it a simple blood test? Reason: am on Vioxx for joint pain; will start Foxamax for increase in bone density. The RX will do no good if I lack Vit A&D. Also,what's a good way to increase Calcium without increasing dairy intake? Someone told me to take a TUMS tablet for the calcium???