In order to get tested, you must be "at risk" e.i. a man who has sex with men, a sex worker, anyone who engages in receptive anal sex.. there are probably a few more categories I am forgetting. Or you must be exhibiting symptoms of an STI. They'll give you a sheet of paper to check off these things- lie if you need to in order to have them accept you for free testing. It's meant to be an emergency service and not a regular check-up place, so that's why they have those limitations in place.

I used to go to the DOH places but prefer Callen-Lorde now because they're much more accepting of providers. I still suggest the DOH clinics to anyone who wants to get tested for free.
 

clinics test for trichomonas vaginosis? Planned Parenthood doesn't, nor does the free one in Chelsea. A doctor will, but you usually end up paying a bunch of money (if you don't want it showing up on your insurance bill)  

Trich is among the most common STDs, and it's possible to get it even with a condom, in the same way as chlamydia and gonorrhea (lower chance, but possible). It's typically silent in men, and often silent in women, but women have more symptoms. It's pretty harmless overall, but if one is married or in a LTR, it's a relationship killer, because it's really not explainable as anything other than an STD.

A note on Planned Parenthood - it isn't free, but the cost is closer to $100-150.