Limitations of a physical examination for diagnosis
Diagnosis of genital herpes solely by a physical examination is not always reliable because the condition can resemble genital ulcers caused by other factors (e.g. syphilis, physical trauma or Crohn's disease). Some of the signs of genital herpes can be confused with common conditions such as candidiasis (thrush), urinary tract infections, and skin conditions that affect the genitals.

Accurate testing is needed to help you decide on optimal treatment
Diagnostic testing for HSV infection is more reliable than physical examination alone. Your doctor will offer you a physical examination and discuss your medical history with you. If he or she suspects you may have genital herpes, they may test you for the virus. Once you have a diagnosis, suitable treatment can be offered to you.

Distinguishing HSV-1 from HSV-2: Type-specific testing
Some tests can tell you whether you are infected with HSV-1 and HSV-2. This can be helpful, as it gives you an idea about the possible severity of your symptoms in the future. Together with your doctor you can then make a more informed decision about how you would like to treat your condition. For example, HSV-2 infection of the genitals tends to cause more frequent and severe outbreaks than HSV-1 (although there are exceptions to this pattern). This may mean that you and your doctor wish to consider a treatment approach that can suppress future outbreaks.

Detecting HSV infection

Virus detection tests (swabbing from the affected site)
HSV can usually only be detected at the site of infection when there are outward signs of a herpes outbreak. A moist cotton wool swab is rubbed against the affected area to collect the virus and then tested, usually in the laboratory. Tests that detect the actual virus or parts of the virus are called 'direct detection tests'.

Only a direct virus detection test can definitively confirm genital herpes.

Most virus detection tests, including culture (where the sample is 'grown' in a laboratory), can be used to distinguish HSV-2 from HSV-1.

The tests are most sensitive if the herpes lesions are swabbed early in an outbreak. It is important that you visit your doctor for testing as soon as you experience the first symptoms of an outbreak.

Virus detection tests are not suitable in all situations - for example after lesions have scabbed and healed or if you are experiencing recurrent bouts of genital discomfort or pain but there are no lesions visible or accessible e.g. in the cervix or the urethra. In these situations, serological tests are more informative.

Serology (blood) tests
When you first become infected with HSV, the body produces antibodies specific for the virus, either HSV-1 or HSV-2. These antibodies are detectable after a few weeks and remain permanently in the bloodstream. Hence, a blood test to detect antibodies to HSV-1 or HSV-2 will say whether or not you are infected. These blood tests are sometimes called 'serology' or 'antibody' tests.

A blood test for HSV can only tell you whether you have been infected with HSV at some time in your life. It does not indicate the site of your infection nor prove that any genital discomfort or lesions you are currently experiencing are due to HSV infection. Some tests only detect HSV-2 but modern blood tests can distinguish between HSV-1 and HSV-2 antibodies.

Blood tests that identify whether you have HSV-1 or HSV-2 antibodies (known as type-specific serology tests) play a major role in identifying those cases that have unrecognised symptoms or no symptoms at all. Blood tests are currently available as either laboratory-based tests or point-of-care tests. Point-of-care tests have the benefit of providing rapid results (approximately 10 minutes), allowing a quick decision to be made about further testing, treatment and counselling requirements. These are not yet available in all countries, so discuss these with your doctor.

Your doctor will explain what your test results mean and whether or not they confirm that you have genital HSV infection. As with many clinical tests, 'false negatives' and 'false positives' can occur occasionally. Repeat testing may be necessary, along with further consideration of your other personal risk factors .

What to do if you think you may have genital HSV infection

• If you feel you may have genital HSV infection you should talk to your doctor. Only he or she can provide an accurate diagnosis and effective treatment.
    
• If your doctor thinks that you need to be tested for HSV infection, ask him or her which sort of test they propose to use, i.e. a swab for direct detection of virus or a serology (blood) test.

Make sure that if a direct detection test e.g. virus culture is proposed, you have genital symptoms at the time the swab is taken. You may need to arrange a separate appointment for this.

Explain to your doctor that you already understand how HSV-1 tends to recur less frequently than HSV-2, and that if your test result is positive, you would like to know which virus subtype is causing your symptoms. You are then encouraging your doctor to request type-specific HSV testing.

If you have had two or more negative virus detection tests (swabs) and continue to suffer from recurrent genital symptoms, ask your doctor if a serology (blood) test would be appropriate. Explain to him or her that you realise that a serology test does not identify the site of HSV infection, but that it can indicate whether you have been in contact with the virus and that you understand HSV-2 is the most common cause of genital herpes. This should encourage your doctor to request a type-specific serology test.

What is available?
More recent virus detection tests, or those used in research laboratories are type-specific. Virus culture is the most widely used direct detection test and can distinguish between HSV-1 and HSV-2, but unless specifically requested, this is not done routinely.

Type-specific serology tests analysed in the laboratory include those made by Gull/Meridian and MRL Diagnostics.

One particular HSV-2 specific serology test can be performed, and the result given, at the time of your visit. Your doctor may or may not be aware of this, since this test (made by Diagnology ) is relatively new. Be prepared for your doctor not to know about this test, or not to have it available.

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• Remember to return to your doctor to collect your test results. There is no need to be embarrassed, your doctor will have seen many cases like yours and he or she is the person best equipped to help you manage genital herpes