# Help me understand STD test results? **URL:** \ **Category:** Factual Questions\ **Created:** [March 12, 2003, 8:46am UTC](https://boards.straightdope.com/t/help-me-understand-std-test-results/160789 "2003-03-12T08:46:04Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![abby](https://avatars.discourse-cdn.com/v4/letter/a/48db29/32.png) [@abby](https://boards.straightdope.com/u/abby)\ **Post date:** [March 12, 2003, 8:46am UTC](https://boards.straightdope.com/t/help-me-understand-std-test-results/160789/1 "2003-03-12T08:46:04Z")
Hiya In the course of my work, I need to ensure that some people have been thoroughly tested for STD’s. To date, there have been many problems with getting comprehensive results. The people who are getting the test don’t really know what to ask for, and the sexual health clinics are severely overworked, and generally do not seem that interested in people who live “low risk” lives. I kinda see their point - people who live high risk lives should certainly be able to get STD tests as easily as possible, but other people can get sick too. Sooo, I figire if I give these people a list of things to ask for, we can ensure that the right tests get done. From what we have done so far, I have established to declare someone thoroughly tested for STD’s, they need to ask for (we’re talking girls only): Blood test:[ul]HIV RPR TPHA (Syphilis) TPPA HEP B [/ul] Vaginal swab (or urine sample?) are:[ul]HEP C Neisseria Gonorrhoeae Chlamydia trachomatis DNA Herpes Simplex [/ul] What have I missed? What is un-necessary? What are TPPA and RPR - do they have “lay” names? Thanks in advance. Abby ---
**Author:** ![jlsmith57](https://avatars.discourse-cdn.com/v4/letter/j/4bbf92/32.png) [@jlsmith57](https://boards.straightdope.com/u/jlsmith57)\ **Post date:** [March 12, 2003, 7:54pm UTC](https://boards.straightdope.com/t/help-me-understand-std-test-results/160789/2 "2003-03-12T19:54:07Z")
Hep C is done as a blood test in our lab. I would think it would be much harder to have it done on a vaginal swab or urine. RPR stands for Rapid Plasma Reagin. It is a screening test for Syphilis. In our lab we run the screen and if it is positive we automatically do an FTA (Fluorescent Treponemal Antibody). Treponema pallidum is the organism that causes Syphilis. I would guess your TPHA and TPPA the TP stands for Treponema pallidum but we don’t have those specific tests at our lab. We would only test for Herpes with a swab on an active lesion. Just a regular swab when the patient does not have a outbreak would not be conclusive. There is a blood test for Herpes antibodies but it can be difficult to interpret because it can cross react with other virus antibodies and would be positive if you had Herpes mouth sores (cold sores). The list you have is the list we use for screening in our pre-natal clinic. So I think you would be pretty safe going with what you have listed. But there are probably some physicians on the board that could confirm that. ---
**Author:** ![abby](https://avatars.discourse-cdn.com/v4/letter/a/48db29/32.png) [@abby](https://boards.straightdope.com/u/abby)\ **Post date:** [March 13, 2003, 8:57am UTC](https://boards.straightdope.com/t/help-me-understand-std-test-results/160789/3 "2003-03-13T08:57:37Z")
Thanks for the info, much appreciated. ---
**Author:** ![Tal](https://avatars.discourse-cdn.com/v4/letter/t/54ee81/32.png) [@Tal](https://boards.straightdope.com/u/Tal)\ **Post date:** [March 13, 2003, 3:02pm UTC](https://boards.straightdope.com/t/help-me-understand-std-test-results/160789/4 "2003-03-13T15:02:03Z")
excellent website for understandign blood test results is [http://www.bloodbook.com](http://www.bloodbook.com) ---
**Author:** ![bernse](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@bernse](https://boards.straightdope.com/u/bernse)\ **Post date:** [March 13, 2003, 5:40pm UTC](https://boards.straightdope.com/t/help-me-understand-std-test-results/160789/5 "2003-03-13T17:40:11Z")
> [@](#): > > \*Originally posted by abby \* > \*\* > In the course of my work, I need to ensure that some people have been thoroughly tested for STD’s. \*\* Curiosity, what kind of job do you have? ---
**Author:** ![js\_africanus](https://avatars.discourse-cdn.com/v4/letter/j/87869e/32.png) [@js\_africanus](https://boards.straightdope.com/u/js_africanus)\ **Post date:** [March 13, 2003, 8:21pm UTC](https://boards.straightdope.com/t/help-me-understand-std-test-results/160789/6 "2003-03-13T20:21:53Z")
> [@](#): > > \*Originally posted by bernse \* > \*\*Curiosity, what kind of job do you have? \*\* Yeah, what kind of photographs are you taking? Can I see them? :lascivious smiley: ---
**Author:** ![js\_africanus](https://avatars.discourse-cdn.com/v4/letter/j/87869e/32.png) [@js\_africanus](https://boards.straightdope.com/u/js_africanus)\ **Post date:** [March 13, 2003, 8:39pm UTC](https://boards.straightdope.com/t/help-me-understand-std-test-results/160789/7 "2003-03-13T20:39:13Z")
Oh, please note from that blood site: > [@](#): > > Tests are rated in terms of their sensitivity (the probability that their results will be positive when a disease is present) and their specificity (the probability that their results will be negative when a disease is not present). A very sensitive test is unlikely to miss the disease in people who have it, however, it may falsely indicate disease in healthy people. A very specific test is unlikely to indicate disease in healthy people. Although, it may miss the disease in some who have it. Additionally you need to know the base rate in the population in question, e.g. AIDS test for straight male who uses condoms and no I.V. drugs. You need this info to find out the odds that a person has a disease given a positive result. For example, take a look at this applet: If the test has sensitivity and specificity both of 95%, i.e. **the test gives the correct result 95 out of every 100 times** , and 1 out of every 100 randomly chosen people in the relevant population has the disease, what are the chances that a person has the disease when she receives a positive result? 0.1897% That is, if I’m doing my math right, in the given risk category **about 19 out of every 10,000 people who test positive actually have the disease**. (Check out Calculated Risks by Gerd Gigerenzer for a better discussion.) In other words, getting a positive result on a test may actually not be that meaningful. You wouldn’t want to destroy somebody’s life because of bad math. Check out Gigerenzer’s book from the library and pay attention to the chapters on AIDS testing and breast cancer screening. ---
**Author:** ![abby](https://avatars.discourse-cdn.com/v4/letter/a/48db29/32.png) [@abby](https://boards.straightdope.com/u/abby)\ **Post date:** [March 14, 2003, 1:12am UTC](https://boards.straightdope.com/t/help-me-understand-std-test-results/160789/8 "2003-03-14T01:12:41Z")
> [@](#): > > \*Originally posted by bernse \* > \*\*Curiosity, what kind of job do you have? \*\* I am a pornographer. abby ---
**Author:** ![Buck\_The\_Diver](https://avatars.discourse-cdn.com/v4/letter/b/ac8455/32.png) [@Buck\_The\_Diver](https://boards.straightdope.com/u/Buck_The_Diver)\ **Post date:** [March 14, 2003, 1:19am UTC](https://boards.straightdope.com/t/help-me-understand-std-test-results/160789/9 "2003-03-14T01:19:58Z")
_Do tell!_ ---
**Author:** ![abby](https://avatars.discourse-cdn.com/v4/letter/a/48db29/32.png) [@abby](https://boards.straightdope.com/u/abby)\ **Post date:** [March 14, 2003, 1:26am UTC](https://boards.straightdope.com/t/help-me-understand-std-test-results/160789/10 "2003-03-14T01:26:18Z")
I started a thread a few months back called “ask the pronographer”, but it got a little out of control - I only shoot solo and girl-girl stuff, and people felt the need to blame^H^H^H ask me why hetro porn is so bad (I got no answer for that, but our stuff is not bad. It’s passionate, real and sexy). Anyway, if you have got any questions, I’d be pleased to answer them. abby