Does anyone know if you can do clinical research as a IRTA?
The IRTA program is primarily intended for those who wish to do basic benchwork. However, I have met premeds in the NIH clinics who assist their PIs on clinical trials. My impression however, was that these premeds did not have a big role on the clinical side and still did a lot of benchwork back in the labs.
My advice, if you are looking at IRTA/CRTA, is to look for PIs that run clinical trials. Most PIs at the NIH collaborate on clinical trials while primarily running labs but a subset do see patients and run labs at the same time. Those PIs would be more amenable to you either shadowing them or taking on some duties on the clinical side, just don't expect too much.
As an aside, in my personal experience, I've met PIs who straight up told me that doing rounds with them or going to clinic with them is expected in addition to my lab work if I joined their lab as an IRTA, so sometimes you may not even need to ask, just mention that you are premed.
Finally, sometimes it doesn't have to be the PI who sees patients. Some labs hire clinical fellows whose sole job is to see patients and run clinical trials under the PI, in that case, you may be able to shadow or work with them to get some clinical experience.
