Everything i have read says that the excess ammonia can be caused by the the excessive ingestion of proteins and as your previous blood tests did not show it but this one did, i would definetely say it has a bearing on it though, but did you tell your doctor and gasto about this, i think it maybe very helpful.
I have had since i was a baby very strong smelling urine (ammonia smell) and i am getting it very very strong again, as a baby i didn't have the sort of baby nappies (diapers) as normal babies have, min smelt strongly og ammonia and i also suffered with constipation my mum used to say it was like putting a nappy (diaper) on a rabbit becasue all she had to do was shake the pellets into the toilet, must have come as a shock when she had my brothers. Oh and another thing i did was projectile vomit, the doctor told my mum it was the baby milk (Ostermilk) that she was feeding me it was too rich, so switched me to Carnation Evaporated milk and thats what my brothers had as well. Truth is i am still suffering similar symptoms (not the projectile vomiting) but i have been diagnosed with IBS, I get very thirsty and do drink a lot of water and tea, at hme i tend to drink carbonated water mainly. It was particularly bad smell this morning and i do not think i had excessive protein , i had Chicken, Stirfry and New Potatoes. I do find that whilst red meet agravates my IBS causing constipation and pain, Chicken, diary and sweetcorn have the opposite effect. I am fed up of telling my doctor the pain and discomfort i feel, i apparently have a fatty liver (in thier opinion caused by excess alcohol intake when i was younger) although i was not an alcoholic, i very very rarely drink now (due to having a very bad blackout and being given an ultimatium from my partner). At the moment i am under the doctor because i have a problem with my knees (i can't kneel) and my ankle where i get sudden pains as though thopusands of wasps are stinging me.
Do you think i should press my doctor and bearing in mind in UK we have a 10 min appointment and doctors here hate it if you have been reading things up on the internet or try to self diagnose, you have little time to tell them whats wrong then they make a decision and quite often you are fobbed off, so although we have free nhs (not free really we pay through our taxes) I think the american system probably works better IF you can afford to see a doctor in the first place