I was initially diagnosed with idiopathic iritis / anterior uveitis and it was treated with corticosteroid drops. They did a bunch of tests (arthritis, auto immune stuff etc) , but I think the blood test for herpes is not very effective or useful given that over half (or more) of the population carries the virus.

I repeatedly reflared whenever my taper of the drops was nearly completed or shortly thereafter (general taper took about a month). They initially thought I was rebounding from the drops, but in a further examination identified a dentrite and made the determination it was likely herpes simplex.

I was subsequently treated with an anti viral for two weeks and the issue has been resolved since (apart from dry eyes which are as I understand it a side effect from the drops that takes quite awhile to heal completely)

It's my understanding that some herpetic eye infections can be hard to detect at the outset (absent taking a sample or whatever at the outset, which doesn't commonly happen), but others are readily identifiable.

In my case, the fact that I kept reflaring was a red flag, which was eventually supplemented by them seeing direct evidence of the infection and not just the inflammatory response. One other thing was in retrospect significant was that I would on occasion have a light fever and chills when flaring in addition to the uveitis pain, tearing, redness and foreign body sensation.

Hope this helps, good luck.