Hmm.. Some wild info getting thrown around in this thread. Im a paramedic, I dont claim to be a master of biochemistry, but I understand body ph. As mentioned previously, your normal range is 7.35-7.45. Theres some room for variation here, but any lower than 7, or any higher than around 8 and you would cease to exist. Ph is basically controlled by your central chemoreceptors and is directly related your CO2 levels in your spinal fluid(CSF).
Sticking a Blue lab probe in your piss, although amusing, isnt giving you proper systemic ph readings.
It for sure isnt as good as a blood test, but if morning urine is used in conjunction with taking samples for a week, you can average them out for a rough idea.