Consequently, you may already have the virus. A doctor can determine this with a blood test for Herpes 2 (Ig), a type-specific immunoglobulin. If you are already infected, you won’t be at risk for a new infection — you and your boyfriend already share the virus. But knowing your herpes status will tell you whether you are capable of infecting a future partner.
A doctor will base a presumptive diagnosis on information provided by the patient and on the physical examination. The characteristic appearance of the herpes sores leaves little doubt about the diagnosis, so the typical appearance of the sores is key to the diagnosis. This appearance helps distinguish oral herpes from oral thrush, shingles, gonorrhea, and syphilis. In addition, chapped or sunburned lips can resemble oral herpes, but the tissue stain (Tzanck smear, see below) shows no virus-induced cell changes. Further testing is usually not necessary but is sometimes done.