Diagnosis of Genital Herpes
Initially, your doctor will ask about your symptoms and medical history, and perform a physical exam.
It is important for you to be open and honest with your doctor about your symptoms and even your sexual history. Your doctor needs this information so that he or she can properly diagnose you and provide you with the treatment that you need. Your doctor will not judge you or your behavior. By understanding your symptoms and your infection, your doctor will be able to prescribe the treatment that is right for you.
Sometimes genital herpes is easy to diagnose because the blisters or open sores around the genital area are easily visible. However, just examining the sores or the rash is not enough. Also, you can have genital herpes even if the sores are not visible.
Lab tests will be done to determine if the herpes simplex virus is in your body. These tests will also be able to tell you if your infection is due to HSV-1 or HSV-2.
There are three types of tests to check for genital herpes.
If your infection is visible, your doctor will rub a swab (similar to a Q-tip) over an open sore or blister to collect some cells. The cells are then tested to see if the virus is present in those cells. It is recommended that this culture test be taken within the first 48 hours after symptoms appear. The problem with this test is that if your body’s immune system already killed the herpes virus from that sore, the test may come back negative or saying to your doctor that you do not have genital herpes, even if you do. This result is called a false-negative diagnosis.
Polymerase Chain Reaction (PCR)
PCR is a molecular diagnostic test. It identifies the virus’ genetic material. PCR is widely used to detect HSV in hospitalized patients. But, it is only now being used more often to identify the cause of HSV. PCR is much faster than viral culture with the results often available within a few hours. It can also identify the virus if it has been damaged by the body’s immune system and may not grow in a standard culture. PCR may not yet be available in all communities, and it is of use only when you have a sore. If you do not have sore, then a blood test will be used.
Your doctor may choose to do a blood test. These blood tests are also called antibody tests because they measure HSV antibodies—the disease-fighting substances in the blood. If the blood tests show HSV antibodies, you are most likely infected with HSV.
Newer tests can even distinguish between HSV-1 and HSV-2. The most accurate way to differentiate between the two types is made by assessing glycoprotein G (gG). The Centers for Disease Control and Prevention (CDC) recommends that all blood tests for herpes now be based on the assessment of gG.
To get a more accurate blood test, wait at least 12-16 weeks from possible exposure to herpes so that your body has enough time to develop antibodies.
Specific tests that your doctor may use include:
- Point of Care test (SureVue or biokitHSV-2 Rapid Test) —Right in your doctor’s office, your doctor can prick your finger to get a small blood sample. Results are available in less than 10 minutes. This blood test checks for the presence of HSV-2 antibodies.
- HerpeSelect ELISA —Your doctor will send you to a lab that will draw your blood (from a vein in your arm) for testing for HSV-1 or HSV-2 antibodies. Results are available in approximately 1-2 weeks.
- HerpeSelect Immunoblot —Your doctor will send you to a lab that will draw your blood (from a vein in your arm) for testing for HSV-1 and HSV-2 antibodies. Results are available in approximately 1-2 weeks.
- Captia HSV IgG Type Specific ELISA —Your doctor will send you to a lab that will draw your blood (from a vein in your arm) for testing for HSV-1 and/or HSV-2 antibodies. Results are available in approximately 1-2 weeks.
Ashley RL, Wald A. Genital Herpes: Review of the epidemic and potential use of type-specific serology. Clinical Microbiology Reviews . 1999;12(1):1-8.
Centers for Disease Control and Prevention. Sexually transmitted disease treatment guidelines 2006. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/std/treatment/2006/genital-ulcers.htm . Accessed July 27, 2010
Diagnosis & diagnostics. International Herpes Alliance website. Available at: http://www.herpesalliance.org/diagnostics.htm . Accessed: July 18, 2005.
Genital herpes fact sheet. Centers for Disease Control and Prevention (CDC) website. Available at: http://www.cdc.gov/std/Herpes/STDFact-Herpes.htm . Accessed July 18, 2005.
Health matters fact sheet: genital herpes. National Institute of Allergy and Infectious Diseases website. Available at: http://www.niaid.nih.gov/factsheets/stdherp.htm . Accessed July 18, 2005.
Herpes blood tests quick reference guide. American Social Health Association website. Available at: http://www.fylrr.com/archives.php?doc=blood_test.pdf . Accessed July 18, 2005.
Strick LB, Wald A. Diagnostics for herpes simplex virus: is PCR the new gold standard? Mol Diagn Ther. 2006;10(1):17-28.
Last reviewed September 2010 by ]]>Lawrence Frisch, MD, MPH]]>
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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