A metabolic disorder results when an enzyme responsible for the breakdown of our food is defective which results in compounds, also known as metabolites, accumulating in blood or urine. Incorrect metabolism means your body might have too much or too little of a metabolite which can have detrimental impacts on normal growth and development.
Patient should preferably be fasted. At least 1 ml of blood in a heparin tube (orangetop tube) cooled on wet ice. Separate plasma within 1 hour of collection and store and transport frozen.
For diagnosis, samples taken during acute episodes are most suitable.
Non-acute samples: ideally collected after at least 3 hour fast (e.g. early morning), or immediately before the next feed. Samples collected post-prandially may show increases in amino acids.