Why do they not use a tornequet when taking taking blood for bone density

I need your help w/more details.  I've personally had my bone mineral density checked several times via DEXA or DXA (dual energy xray absorptiometry) and never had my blood drawn as a requirement.  I've also had my bone mineral density screened via heel ultrasound, but again, never had my blood drawn as a requirement.  So I must admit to some confusion as to why you had blood drawn for yours and especially why a tournaquet wasn't used.  Having said this, I'm assuming that your bone density was being tested for osteoporosis.

On the other hand, perhaps your physician wasn't so much testing bone density as much as s/he was looking for (abnormal) bone activity, in which case you probably had a bone scan for which an IV line was placed, not to draw/take blood, but to give you a contrast agent so that the radiologist could better visualize your bone activity.

Go ask your physician what test was performed (bone mineral density vs bone scan) and why (looking for osteoporosis or abnormal bone activity).

Good luck!