Noticed A Spot On Penis. Blood Work Showed Negative For Hsv1 And Hsv2 But Swab Culture Showed Positive For Hsv1. Suggestions

Posted on Fri, 22 Nov 2013

Medically reviewed by Ask A Doctor - 24x7 Medical Review Team

Fri, 22 Nov 2013 Answered on

Thu, 12 Dec 2013 Last reviewed on

Question : hello, last week I went to the Dr to check a spot on my penis. he said it is possibly herpes. he took blood work and a swab of the area.. today the office called with my results and stated the blood work came back negative for hsv1 and hsv2... however the swab culture came back positive for hsv1 but not hsv 2... my dr was not in to clarify this with me... I was under the assumption that hsv1 Is on the mouth and hsv2 is on the genitals... also why would the blood work return with negative results.. thank you...

Answered by Dr. Geetika Paul (1 hour later)

Brief Answer: Antibody levels in herpes infection Detailed Answer: Hi, I understand your concern regarding your skin problem and I hope I am able to help you in the same. Now there are two things that you seem to be concerned about. Firstly, I would like to tell you that genital herpes is no doubt largely caused by type 2 virus but there are some twenty percent cases in which genital infection can occur due to type 1 virus. This is what seems to have happened in your case as well. Now the swab culture test is most specific and confirmatory test for this infection. As far as the blood test is concerned, it is essentially an antibody test. These antibodies take a few days after infection to develop. The blood test comes out to be positive only once the antibodies have developed. So, since the culture is positive, so there is no doubt that it is a herpes infection. So you need to start treatment for it as soon as possible. Hope it helps, If you need further clarifications, please ask Dr Geetika Paul

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar