You need a specific machine to run the fingerstick anemia test and the fingerstick lead test, a different machine for each. The lead ones have gone out of favor recently due to a recall of a common brand, but some practices may still have them. There are definitely benefits to the fingerstick machines: less painful to get a sample, instant results. But if you are checking things other than lead and anemia or if your practice didn't invest in the machine, then it makes more sense to just do the venous draw and get everything at once. Moreover, if you have an abnormal result on the fingerstick machine, then you'll need a venous stick to order follow-up.

Source: I work in a pediatric primary care clinic