Can you test positive for herpes without an actual outbreak?

Yes.

Yes, a blood test may be performed. A ‘positive’ test result means, with near certainty, that a person has been infected with the herpes simplex virus, even if that person does not have an outbreak or any symptoms. However, the test is not perfect - sometimes, even when a person has herpes, the test does not detect it. That’s sometimes the case if the infection happened in the past 4 months.