Initial testing When an inherited disorder of metabolism is suspected, evaluation begins with a review of neonatal screening test results and ordering of basic metabolic screening tests, which typically include the following: Glucose Electrolytes with calculation of anion gap Complete blood count and peripheral smear Liver tests Ammonia levels Serum amino acid levels Urinalysis Urine organic acids Glucose measurement detects hypoglycemia or hyperglycemia; measurement may have to be timed relative to meals (eg, fasting hypoglycemia in GSD).