The authors describe a laboratory investigations protocol to be used by pediatricians facing conditions suggestive of inherited metabolic disorders. This protocol includes: 1) an emergency screening to be systematically performed during the acute clinical phase; 2) samplings to be kept frozen for possible secondary specific investigations according to the results of the emergency screening. In addition a perimortem protocol is also presented, to be applied in every lethal situations in which an inherited metabolic disorder is suspected. The equipment required in order for the clinician to properly perform the different investigations is also described.