Hi and thanks for question.
I am afraid that I do now know what you are referring to when you reference index values.
Here in BC, STI results are generally reported to clients and clinicians as positive or negative, reactive or nonreactive, or in the case of syphilis they may attach reference numbers to the results.
Sometimes hepatitis results may indicate values, but these tests are not generally done as part of routine STI screening.
For routine STIs (gonorrhea, chlamydia, syphilis and HIV) testing 3 months after the exposure would cover all window periods (time from exposure to when a test may be able to pick up a positive result).
If the person that tested you has received the results and they are not calling you back in for treatment or for further follow up, you can consider your results conclusive.
Hope this helps.