TB test injections and reading

A medical technical question, not solicitation for advice.

My rescue squad requires personnel to have annual TB tests, which I don’t have a problem with doing. In years past, when the time came up, I conveniently had a regular doctor’s appointmnet already scheduled, and the office was located along my commute route, so I had it done there.

This year, the squad has a contract with the local public health agency to do it free of charge, and I don’t have a doctor’s appointment scheduled in the timeframe.

For purposes of scheduling, what is the window for injection and reading?

The test should be read 48-72 hours after placement.

Thanks. I’ll have it done on a Monday or Tuesday; what I was trying to determine.

The last one I had done was “self read”.

That would be fine normally, but I need An Official Piece Of Paper to get this done.