INS and type 2 diabetes mellitus: Recently, a simple urine test, the urinary C‐peptide creatinine ratio (UCPCR) 13, has been shown both in Type 1 diabetes and Type 2 diabetes, to be excellently correlated with the ‘gold standard’ measure of endogenous insulin secretion, the formal mixed‐meal tolerance test (MMTT), and a sensitive and specific test for absolute insulin deficiency 5.