Testing urine

[Cruze44]

"Adults with or without diabetes who are currently taking an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin II-receptor blocker (ARB) should not be tested for proteinuria (Grade: weak recommendation, low-quality evidence)"

I found this statement on-line while looking for a lab location to test my urine. Does anyone know why they would say not to bother testing for proteinuria if someone takes an ACE inhibitor? I take a mass dose of an ACE inhibitor. Does this cause false readings or something? Or does it put protein in your urine? I have no insurance and have to pay cash for all these test. I'd rather not bother if it's pointless. Thanks for any advice.