[Question #4144] NSU Test Question

30 months ago

Hello Doctors,

 I am married and stupidly had an unprotected drunken 1 night stand with a girl I know which involved up to 10 separate incidents over the night of vaginal sex and fellatio.

I have tested privately (15 days post exposure) in London for Chlamydia, Ghonnoreah, Mycoplasma Genitalium, Ureaplasma, Trich and Herpes and all were negative.

 I am uncircumsized and didn’t want to keep proactively checking every post my exposure but did do on occasion and noticed the following:


-           2.5 days post exposure – a very slight amount of clear, sticky secretion – had been aroused a little earlier so put this down to normal secretion

-          10 days post exposure – 8.10am, a small amount of white/cloudy secretion after defecating (I understand this is common?) and then a bit more 20 mins later which may well have just been from the original secretion 20 mins earlier in the morning. I then checked at 10am, 1pm, 3pm and 5pm and there was nothing there.

-          12 days post exposure – checked at 7am, 9am and 11am and nothing there. I then checked again at 1pm and there was a slight amount of clear secretion, just looked like pre-ejaculate and I think I may have been aroused slightly before so may well have been that.

-          13 days post exposure – checked at 8.30am, 10:30am, 2.30pm amd 4pm and nothing there



Do I need to have swab test for NSU or with my negative tests for all the infections listed can I assume I am ok and there is no risk to my wife from having unprotected sex with her?

Edward W. Hook M.D.
Edward W. Hook M.D.
30 months ago
Welcome to the Forum.  I'll be glad to comment hand, hopefully, relieve your concerns.  You are in the clear.  Your testing PROVES that you were not infected with any of the STI pathogens which cause urethral infection.  That leaves non-chlamydial, non-mycoplasmal NGU which, if present (and I think it is not- see below) is not known to be transmittable to partners or to cause complications.  In your case, you have alternative explanations for the two instances in which you observed normal urethral secretions- following arousal and following bowel movements, both of which are well described to lead to an increase in normal genital secretions.  I see you reason for concern, no likelihood that your dalliance led to acquisition of an STI and no reason for further testing. 

I hope these comments are helpful.  EWH
30 months ago

Thank you Doctor, that’s very useful.

My follow-up questions relate to the sample collection. When I’ve visited NHS clinics in the past I’ve just had to urinate into a cup and then give it back to the Dr. On this occasion at the private clinic I was given a sample collection kit direct from the laboratory  

I had to pee into a small box which had a plastic/cellophane liner and then I had to transfer this into a Sample Tube which I then sealed and gave back to the Dr ready to go direct to the lab. I didn’t give this a great deal of thought at the time but the instructions included to wash my hands first, to ensure it was a first catch sample, to only pee half way into the small box and went transferring the sample into the Sample Tube to not to go beyond the 9ml mark.

1.       I didn’t wash my hands first and touched the plastic/cellophane liner of the box to push it down to ensure there would be no ‘splash back’ before urinating. Would this effect test accuracy?

2.       I peed directly into the initial small box (first catch) but must have gone over the half way may mark as when I transferred it into the sample tube it filled the tube almost to the top (so way over the 9ml mark, I assume probably somewhere around the 30ml mark) – would this have any impact on test accuracy?  

3.       Finally, given the Sample tube was full it meant there was some of my sample still in the initial container box which I then needed to dispose of. My concern is that is could have been this remaining liquid in the initial sample box that had bacteria in that the test would pick up or does the testing not work like that? 

Edward W. Hook M.D.
Edward W. Hook M.D.
30 months ago
Testing of urine has been proven to have statistically equivalent accuracy as testing using swab specimens.   You and have confidence in your test results (I worry that you do not and that you may be overthinking this).  In answer to your specific questions:
1.  Having not washed your hands and having touched the liner of the collection box will have no effect on the accuracy of your tests.
2.  Having collected a larger than specified amount of urine is not know to have a negative influence on test results.  IN fact, for many tests, the recommended specimen volume is 30 ml. 
3.  The testing does not work that way. The bacteria the tests are testing for are present through the freshly collected urine specimen.  That there was some residual urine in the container does not diminish the accuracy of your results. 

I urge you to believe your test results.  EWH
30 months ago
Thanks Doctor, that makes sense, it's just quite confusing why labs provide specific guidance but you explanation makes sense, thank you. 

My final questions if I may (just for final clarification and to ensure I have things straight!):

1. When i mentioned I had noticed some secretions you mentioned in your response that i'd noticed these twice. It was actually 3 times - on 2.5 days, 10 days and 12 days (slight amount of clear secretion. Again, this may have been down to arousal, I can't remember if i had been aroused at some point in the preceeding hours). 

I wasn't checking at all on the other days and I'm not circumsized so may have missed some abnormal secretion if it had been there. 

So, can you confirm my understanding is correct that even on the slim chance that there was non-chlamydial and non-mycoplasmal NSU present, given there is 'no known risk' of transmission to or complications for partners, the risk would be too low to warrant being swab tested? 

2. In my prior research before posting on this site i read that a post from you on the medhelp site that secretion after defecating would usually be clear. In my instance, it was a small amount of white / cloudy secretion. I assume this doesn't change your advice?

3. Finally, i assume the Lab testing instructions which i didn't follow to the letter, as explained below, wouldn't have anything to do with the test testing for MG, UU, Trich, Herpes etc (i.e. those pathogens not routinely tested for) and thus perhaps requiring more specific sample volume etc? 

Thanks for this final clarification Doctor, your advice has been extremely useful and prevented me needless testing further. 

Edward W. Hook M.D.
Edward W. Hook M.D.
30 months ago
1.  Thanks for correcting me.  Nonetheless it does not impact my assessment.  All men have a certain amount of normal genital secretions which typically go unnoticed.  For preceding arousal or a bowel movement to be associated with an increase is well described.  I see not reason for a swab test.
2.  Prostate secretions can certainly be cloudy as well.  No change in my assessment.
3.  As I said above, sample volume would not be expected to change your results.

Hope this helps.  As you probably know, we provide up to three responses to questions.  As this is my 3rd response, this thread will be closed later today.  EWH