What is Involved in a Diagnosis of Herpes?

Diagnosing herpes is typically done through a laboratory with blood tests or a polymerase chain reaction test. Most doctors also perform a physical examination to help with the diagnosis of herpes, but it is unlikely that this examination alone is enough to determine if the virus is present. At a glance, herpes lesions on the skin look very similar to many other types of infections. For this reason, more extensive testing is necessary before the final diagnosis can be made.

Doctors typically cover a patient's history before doing any testing for herpes. This normally involves asking the patient a series of questions relating to their symptoms, whether or not they have had symptoms in the past, and their current and past sexual history. Many patients may be uncomfortable answering questions pertaining to their sex lives, but this information is very important in the diagnosis of herpes.

A herpes laboratory test usually is done after the initial physical examination. Doctors normally use a swab to take a samples of any sores suspected to be herpes. The samples are examined under a microscope to see if the virus present. This method is effective for the diagnosis of herpes, but not always foolproof. It is possible that a doctor will not find evidence of herpes in the samples, even though herpes is present in the body.

The diagnosis of herpes with a blood test may be slightly more accurate. Blood tests will show the presence of any herpes antibodies in the blood, which are indicators of a past infection. The presence of these antibodies indicates that a person is infected with herpes. One downside to this type of test is that it typically cannot distinguish between the two types of herpes: HSV1 and HSV2. Type 1 herpes is the variety that is normally associated with fever blisters and cold sores on the mouth, whereas type 2 herpes is spread through sexual contact and results in genital outbreaks.

A polymerase chain reaction (PCR) test is probably the most accurate test for the diagnosis of herpes. This DNA test not only indicates the presence of herpes, but also determines what type of herpes the patient has. To perform the test, a doctor has to take a sample of either tissue, blood, or spinal fluid from the patient. Results typically arrive within four hours after the test is done. The most accurate results are often achieved if a patient has the test done at the onset of an outbreak rather than waiting until days later.