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Is It Time for a Syphilis Test? Diagnosis and Testing of Syphilis

Medically reviewed by Mae Charisse Antalan, MD · General Practitioner

Written by Giann Floresca · Updated Dec 19, 2022

Is It Time for a Syphilis Test? Diagnosis and Testing of Syphilis

Is it time for a syphilis test? Syphilis tests are encouraged because of the damage syphilis can potentially do to your body. Testing should be performed in patients with symptoms of infection. Those without symptoms but are at high risk of acquiring the disease also need testing.

Syphilis testing is needed because early syphilis symptoms may be mistaken for signs of a different condition.

The initial syphilis sore may look like a a far less serious skin condition. Syphilis also has a tendency to seemingly disappear, taking with it all the symptoms. This gives the patient a false sense of security. However the disease may come back after many years, in a much more advanced state. All of these factors make it important to take a syphilis test.

Is It a Similar-Looking Disease? Take a Syphilis Test

Some diseases which may be mistaken for syphilis include:

  • Cutaneous vasculitis – This group of disorders includes capillaritis, and small, medium, and large vessel vasculitis. They generally cause blood vessels in the skin to become inflamed.
  • Palmoplantar keratoderma – This skin condition includes diffuse keratodermas, focal keratodermas, and punctate type keratodermas. This skin condition causes the excess thickening of the skin.
  • Panuveitis – This is an inflammation of the uveal layers of the eye. This inflammation can affect the other parts of the eye. Panuveitis may lead to vision blurring and even blindness.

What Syphilis Test Do I Take?

Syphilis tests are serologic tests. They can either be nontreponemal or treponemal-specific.

Nontreponemal tests look for reagin antibodies. Doctors use them as initial screening tests. These directly look for the syphilis bacteria or for antibodies for that bacteria.

Doctors use treponemal tests to confirm results. These look for the antibodies directed towards the bacteria themselves. They also look for antibodies directed towards antigens — the toxic substances the bacteria produce. They search for other treponemes (toxins that induces an immune response from the body) as well.

The use of one type of test alone can be insufficient, and can produce false positive results.

Nontreponemal Tests

You will first be screened for syphilis and only given further testing to confirm if the initial screening results turn out positive.

These screening tests include:

  • Venereal disease research laboratory (VDRL)  test – This test looks for a high amount of antibody production to confirm infection.
  • Red plasma reagin (RPR) test – This looks for antibodies produced against syphilis. They specifically look for antibodies directed against the cells already damaged by the infection.
  • Rapid immunochromatographic test – This test uses a nitrocellulose strip, similar to a pregnancy test. The strip contains a mix of antigens and a selenium colloid (a serum) which reacts to antibodies against syphilis. Just like a pregnancy test, the area with the colloid will show up as a line if there is a reaction between the antigen-selenium mix and the antibodies that the test is looking for.

Treponemal Tests

More detailed tests to confirm syphilis include:

  • Fluorescent treponemal antibody absorption (FTA-ABS) test – This test looks for compounds present in antigens found on the surface of the bacteria. A special light source and filters illuminate those compounds in the antigen. This causes the antigen to glow, making the bacteria far easier to locate.
  • Dark-field microscopy – Dark-field microscopy darkens the areas around the observed bacteria to make it easier to observe. It filters out the unnecessary parts of the image and amplifies the observed object. This creates a stark contrast of a nearly black background with bright objects in it.
  • Polymerase chain reaction (PCR) test – This test uses the bacteria’s DNA and makes millions of copies using advanced machinery. This will make it easier to observe and identify the bacteria present in the sample.

Key Takeaway

In conclusion, testing and diagnosis for syphilis have become fairly advanced and very reliable. These include nontreponemal and treponemal-specific tests. As long as you can detect the infection on time and have it treated, you can say goodbye to syphilis.


Learn more about Syphilis here


Hello Health Group does not provide medical advice, diagnosis or treatment.

Medically reviewed by

Mae Charisse Antalan, MD

General Practitioner

Written by Giann Floresca · Updated Dec 19, 2022

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