Welcome to the Forum.  I'll be glad to provide some information.  Trichomoniasis is one of the most common STIs and is most often asymptomatic in both men and women.  When symptoms are present there may be mild discomfort on urination, or a small amount of clear urethra discharge.  Currently available PCR tests are the most sensitive tests for trich diagnosis in men and while a swab may be somewhat more sensitive than urine, the difference you describe is higher than most experts would suggest.  That estimate is based on a single study.  In your case, if you have had 4 initial void urine specimens which were negative for trich you can be confident that you were not infected.  The medication you mention, tinidazole is related to metronidazole and is one of the medications recommended for trichomoniasis treatment and is typically given as a single 2.0 gram dose.  Between the testing you have had and the medication you have taken, you should be confident that you do not have trichomoniasis, if you ever did.

Less than half of women with trich are symptomatic, typically with a vaginal discharge or irritation. 

I hope this information is helpful.  EWH

Yes, there would be WBC present in a discharge related to trich. 

The medications work quickly with symptoms resolving in a day or two.

Trich does not clearly cause complications but it can be uncomfortable for some persons with infection.

Yes, in some men the infection will clear itself over a week or two.  EWH

I'm not sure what the basis for your concern is.  Further, I would suggest you stay off the internet.  If that is where you heard that trich could be acquired through oral sex, you have accessed an unreliable source.  Trich is almost never acquired or transmitted by oral sex.  Similarly there is little risk of transferring trichomonas by the transfer of genital secretions on one person's hands to another person's genitals. 

Yes as I said above, the recommended treatment for trich is 2.0 grams of tinidazole, orally once.  The regimen you mention taking was more than enough to cure trich if you had it.

This is my third reply to this series of questions. Thus, as per Forum guidelines, the thread will be closed in a few hours. Take care.  EWH