Yes, you walk in to join the virtual line. What you must know (from my experience) I arrived at 7:50 am and the line was wrapped to the apartments on Lex trailing down to the train station. By the time I got up to get my name on the virtual list, they had about 60 spots left as they only take a certain amount of people a day. Take this into account when going to join the line. Also, I (I live on 69th so it wasn't a big deal for me) wasn't called back for my test until almost 1 pm so it was a 3-hour wait before I got my text message, be sure you have somewhere to wait.
You have to go in to put your name on the waiting list. They call you back when it is your turn. Try to go earlier in the day.
Better off if you go to a nyc health and hospital or nearby clinic.
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