Explanation Of VDRL And TPHA Serology Tests
Morning. Okay, I want to ask about VDRL and TPHA serology tests. Are the results of both tests can show false negative results, meaning that test results can be wrong? What might be positive test results but it becomes negative. Thank you.
Thank you for the question.
VDRL and TPHA serological tests are usually done to detect syphilis caused by the bacterium Treponema pallidum. In general, syphilis serology tests are divided into two types, namely:
Non-treponema test. An example is the VDRL or Venereal Disease Research Laboratory which detects antibodies to Treponema pallidum cells unspecifically, because these antibodies can appear in other infections, so this test is nonspecific (prone to false positives) and is usually used as a screening due to its lower cost.
Treponema test. An example is TPHA (Treponema Pallidum Haemagglutination Assay), which specifically detects antibodies to Treponema pallidum cells. Therefore, usually when the VDRL results are reactive, it will be confirmed with this TPHA test.
To answer your question, both tests can show false negative or false negative results, where the test results are negative, when in fact the person is infected with the bacterium Treponema pallidum. This usually occurs in early-stage infection, which is about the first three months after infection, where the body has not produced antibodies that can be detected by both of these tests. Therefore, usually the doctor will adjust the results of investigations with a history of complaints and physical examination results to determine the diagnosis and therapy for patients.
Hopefully this information can help.