Reassure her, that being tested, is nothing to feel dirty, nor ashamed about. If anything, it's normal, in this day and age, to be tested after having a relationship end, or even to be tested before a relationship begins.

After my divorce, I had myself tested for everything. I came back normal. Ironically, a year later, my exh went and had himself tested for everything. Which came back normal.

It's normal, to have these tests done!! It's actually, good to have these tests done.

You are being tested, with her!! And that's a bonding experience. And then, you can both put this behind you.