How long would it take herpes to show up on a blood test?

<2 weeks: It usually take1-2 weeks for a healthy immune system to produce IgM anti-bodies to a viral infection. There are 2 types of herpes simplex 1 and 2, so both tests are available. If a patient has IgG herpes antibodies then the patient has already been exposed 'some time ago.' hope that helps.

2-6 weeks: There are variations in individual immune response and it could take 2-6 weeks to detect antibodies in blood. Have a healthy diet, exercise, drink plenty of water, have safe sex, and get HPV vaccine. Wish you good health! Nutrition: http://www.choosemyplate.gov/.