Answer:
Dear
Harshit,
Serologic
herpes tests (blood test) work by measuring the levels of Herpes simplex
antibodies inside your body.
Antibodies
are substances produced by your immune system to fight off infections
(such as herpes).
Serologic
tests detect herpes by looking for antibodies in the blood or serum.
Blood
tests can be performed even when there are no symptoms present. If
the herpes antibodies are found in the blood, it means that herpes
simplex is latent in the body.
Serologic
(blood) tests do not require swabbing a lesion, so they can be done
long after symptoms have faded.
This method of testing has the advantage that it can be done even
when a person has no symptoms, so it is a very effective way to detect
an established herpes infection.
Type-specific
blood tests are ideal for those who have had a history of genital
symptoms but have never had a successful confirmatory test.
The sensitivity
(the likelihood of the test correctly diagnosing herpes) and specificity
(the probability of a test correctly) determining that a patient does
not have herpes of blood tests is better than culture or antigen tests,
but there are two important factors to consider:
Timing.
If this is the first exposure to herpes, a person may take several
weeks to develop the antibodies that blood tests look for.
Conflicting
results some blood tests cannot tell the difference between the two
types of herpes simplex, HSV-1 and HSV-2 (the cold sore and genital
herpes viruses)
For this
reason, anyone seeking an accurate diagnosis of their herpes type
should request a type-specific test, which can accurately distinguish
HSV-2 from HSV-1 antibodies.
People
who are getting a type-specific test for genital herpes should ensure
that the test they receive detects antibodies to gG2 since there are
still blood tests out there which claim to be type-specific but which
are not.
Remember:
A positive
blood test simply indicates that the person has been infected with
type 1 or type 2 HSV (or both) some time in the past.
A positive
blood test does not indicate the site of the infection.
Serology
tests do not provide any information about whether symptoms (genital
or oral) are due to herpes.
A positive
blood test does not tell if the person is infectious at the time of
the test.
