Hi Christopher,
Unfortunately it's pretty rare to be able to get diagnosed at a "local" or small hospital. Even major university hospitals sometimes do not have the expertise. It would be unusual to lose weight because of not eating protein, but you could try increasing carbohydrate calories until your appointment. If you would like to talk more or need a referral, please feel free to email me at Cindy@nucdf.org
Plasma quantitative amino acid levels are generally used to screen for the disorders; low or high levels of some specific amino acids occur in those affected, but the levels need to be obtained after fasting for at least four hours. It also takes significant expertise in urea cycle disorders to be able to interpret the levels appropriately. In some cases, the levels are fairly normal and other lab tests need to be obtained, and ultimately DNA or fibroblasts for mutational analysis. The sample is sent to one of the three or four existing labs that do this analysis.
Cindy Le Mons
Executive Director
National Urea Cycle Disorders Foundation