Dear Dr. Hook or Handsfield,

following low risk exposures I had syphilis testing. The German lab did 2 (?) CMIA Screening tests (I suppose). The results said: "Lues-Screening: negative" and in the next line "Lues-Screening, quant.: 0.04 S/CO" with a reference range < 1.00. I`ve complied with a window period of 6 weeks.

My questions:

1.) Could the low 0.04 S/CO value by any means indicate a very low "positive" result and a later test may indeed end up positive?

I guess I can predict the answer and I do hope for this confirmation.

If so:

2.) Why does the test detect any "antibodies" (or markers?) at all if in fact there is no infection?

And

3.) Can I safely totally disregard this 0.04 and take my test as rock-solid proof that I am indeed not infected with syphilis?

I have stayed away from the forum for more than half a year and I hope that an answer to this question will also help other users who tend to not believe their test results.

Otherwise I do still work with a profound counselor who helps me with my underlying problems and we agree that I am on a good way.

Have a lovely Christmas season!

Kind regards

Karl 

I'm going to start with a pretty technical explanation -- but knowing something of your background, I'm confident it won't be a problem. The technology for the HIV antibody and antigen-antibody tests is called enzyme immunoassay (EIA), also called enzyme-linked immunosorbet assay (ELISA). For almost all EIA tests, for HIV and many others, the biochemistry of the test results in a numerical value that essentially compares the strength of a chemical signal in the test specimen with that in a control built into the test procedure, and the reported number is the ratio between the test and control results. For example, a result of 2.0 means the optical density (OD) of the test read-out was twice that of the control. For most EIAs, including most HIV tests, <0.9 is negative, 0.9-1.1 equivocal, and >1.1 is positive. Importantly, the number is not a measure of the amount of antibody in a sample. All values below the 0.9 cut-off are equally negative and indicate complete absense of antibody. No sample ever gives a zero result (mathematically, zero is not a possible outcome in any ratio).

So your result of 0.04 is completely negative. It does not suggest you have a little bit of HIV antibody in your blood. In fact, the same sample tested 10 times would usually give 10 different numbers -- which could vary widely (e.g. 0.04, 0.2, 0.6, or even 0.85 all are equally naegative).

Those comments address all three of your numbered questions, but let me know if anything isn't clear. Best wishes--

HHH, MD

Dear Dr. Handsfield,

thank you for your rapid and profound answer and your kind words. I appreciate it!

The testing that`s been done was Syphilis (not HIV) and the technology is called CMIA (Chemiluminescence Microparticle Immunoassay) which to my knowledge has basically the same mode of action as EIA. Anyway the technique indeed compares the strength of a chemical signal in the test specimen with that in a control built into the test procedure, just as you described it.

And the reference range was defined as < 1.00 whereas my result was 0.04 S/CO (signal against control).

So I really have only 2 questions for complete reassurance:

1.) Your answer "0.04 is completely negative" is equally correct for syphilis, right?

2.) No more testing is necessary, right?

Again, I thank you for your compassionate, profound, non judgemental and always timely answers.

Keep it up!

So will I with my underlying challenges.

Happy Christmas season!

Karl

 

Thanks for your thanks, once again.

I have only one more question that has arisen. Within the window period of this test I had exactly one "exposure". She was clothed and massaged my back and butt. When I turned around I masturbated myself so she even did not touch my penis. There is just one thing that concerns me: She quickly gave me a peck on the shaft of my penis. It happened suddenly and it was just a fraction of a second, a really superficial quick peck. I wonder if she had a sore on her lips (I did not see one) if syphilis could even be transmitted by such fleeting, superficial, quick contact. What would be your estimated transmission risk in that scenario? And I guess no testing is needed, right?

I wish you all the best for the remaining days of the year and all the best for 2023.

Kind regards

Karl 

Thanks for the kind wishes. Happy new year.