1040 would be fine with me, or a documented disability (drunks, drug addicts, fatties and most mental patients ought to go get a damned job, too), or proof that the patient is under the age of 18.
And no, the US is not 37th in the world in terms of healthcare. The first time I heard that, I knew it was so absolutely ludicrous that looked it up.
I found that the ranking is by the W.H.O., whose motives and criteria are questionable at best. Their criteria have nothing to do with life expectancy or cancer cures or infant mortality, but rather are based on "Accessability to healthcare". That is a totally meaningless, subjective criteria, which exposes their true, socialist, motive.