Herpes Simplex Virus Type 1 Antibody, Detecting Nucleic Acid (Serum/Plasma)

Your doctor may order this test if you have symptoms that could be caused by the herpes simplex virus, such as blisters or sores around the mouth or genitals, or if you have been in close contact with someone who has an active infection. It may also be part of an evaluation when the cause of your symptoms is unclear.

Your healthcare provider may recommend this test if you have symptoms like cold sores, recurrent mouth ulcers, or if you’re at higher risk for HSV-1 exposure (e.g., due to immune conditions or sexual history). It can also be used for screening in certain clinical settings.

This test looks for signs of herpes simplex virus (HSV) infection, either HSV-1, which commonly causes cold sores, or HSV-2, which is more often associated with genital herpes. Depending on the type of test, it may detect the virus itself, viral genetic material, or antibodies your immune system produces in response to the infection.

The test detects antibodies produced by your immune system in response to HSV-1. These antibodies indicate that your body has recognized and fought off the virus at some point, even if you no longer have active symptoms.

If your provider is testing an active sore, a small swab will be gently rubbed against the affected area to collect a sample. For a blood test, a routine blood draw is performed, and no special preparation such as fasting is usually required. Tell your provider about any medications you are taking, especially antiviral drugs, since they can affect the results.

A blood sample is taken from a vein in your arm. The blood is processed to separate serum or plasma, which is then tested for the presence of HSV-1 antibodies using a specialized nucleic acid detection method.

A positive result means evidence of HSV was found, which indicates a current or past infection depending on the test type. A negative result suggests no infection was detected, but false negatives can occur, especially if the sore is healing or the sample was taken early. Your provider will interpret your results alongside your symptoms and medical history to recommend appropriate treatment or follow-up.

A positive result suggests past exposure to HSV-1, meaning you likely had the virus at some time. A negative result means the test did not detect antibodies, but this does not rule out past infection if the test was not done at the right time.