[Question #12892] Syphilis test

4 months ago

Dear Doctor,

I have been in contact with you before through this forum (Question #12743).

However, after my last sexual contact with a man (tongue kissing and jerking each other off on February 21), I had myself tested by my doctor (blood analysis of blood from a vein).

I had the test done on April 3.

The report from the lab said the following:

Treponema pallidum As - reference value: <0.8 - patient value: 0.2

Treponema pallidum axis: negative

Is this test reliable at the time I did it (41 days after last contact)?

I had also had a test done in January. Then my value was <0.1.

Is the increase in my last test (to 0.2) worrisome? For example, could this indicate an early stage of infection or is this a normal?

Thanks in advance!

Edward W. Hook M.D.

4 months ago

Welcome back to the Forum. On this occasion I'll be answering your questions. To prepare to respond, I reviewed your earlier interaction with Dr. Handsfield and agree with all that he said. Your risk for syphilis from the encounter you describe was miniscule. Your repeat testing confirms that the spot you noted on your tongue was NOT syphilis and rules out any possibility that you acquired syphilis from your encounter. The "baseline"/negative values for syphilis tests of the sort you describe can fluctuate from day to day. This variation is due to factors such as temperature, the test batch used, and many other variable. Irrespective however, a negative value is a negative result and the fact that your recent negative result gave a slightly higher value than previous tests is of no concern whatever. You can be entirely confident that you did not get syphilis from the encounter you describe. There is no need for further testing. It is time to put your concerns aside and move forward. I hope my comments will help you to do that. EWH---

4 months ago

Dear Doctor,

Thank you so much for your quick and comprehensive explanation!

Let me outline my timeline a little more clearly:

Test 1 on January 22, 2025. I took this test because I had sex three months before. So for that encounter I am 100% sure I did not have syphilis.

On February 21, 2025, I had a new contact with a man (jerking off and tongue kissing each other).

On March 1, I developed eczema on and between my fingers. On March 11, I developed a sore throat and neck pain. These symptoms persisted for about three weeks.

On April 3, I then got tested for the contact on February 21. So this test was taken at 41 days. This one was also negative.

So the test in January was not for the same sexual encounter as my test in April.

The test in January had a value of <0.1. The test in April had a value of 0.2

I was just worried now because I have a sore throat again since yesterday and because the value of my last test was higher than a previous negative test.

If I understand correctly a syphilis test is reliable after six weeks?

The higher value is still not worrying now that you know this test was taken following a new sexual encounter (jerking off and tongue kissing each other)?

So if I understand correctly, I really shouldn't worry anymore (even now that I have a sore throat again) because my test was negative at 41 days?

Thanks in advance for your response and my apologies for the many questions!

Edward W. Hook M.D.

4 months ago

You are correct. There is NO reason to worry. When symptoms are due to syphilis, tests are ALWAYS positive, no exceptions. Further, tests at 41 days are conclusive.

It's time to stop worrying. EWH

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