Can simplex herpes show up on blood tests?

Depends. A blood test is available for diagnosis of herpes. However, it is not a routine test and your doctor would need to order it.
Herpes Testing. Yes. Herpes can be tested for with a simple blood test. There are two ways of testing for herpes, one is in an acute setting in the first few months after an exposure. This is the igm antibody testing. Then after the first month or so the igg antibody test can be done to see if one has been exposed and infected with herpes type one and type two.