Biochemical Studies

Abstract

Evidence for the presence of an inherited metabolic disease is often derived from detailed clinical evaluation of the patient and examination of the family history. Important stumbling blocks in identifying an inherited metabolic disease include the fact that signs and symptoms are often nonspecific, leading to initial testing to exclude routine childhood illnesses and delaying consideration of metabolic disorders. Sometimes suspicion arises from unexpected pathological results of basic laboratory investigations and/or imaging. Absence of acute metabolic decompensation (e.g., hyperammonemia, hypoglycemia, overwhelming metabolic acidosis, anion gap) does not rule out an inherited metabolic disease.

Even when appropriately suspected, ordering physicians may be unfamiliar with important biochemical interrelationships and the appropriate diagnostic tests to order, occasionally leading to inappropriate sample collection and storage. Consultation and coordination with a licensed clinical biochemical genetics laboratory helps to insure that appropriate tests are ordered, the correct samples are obtained, and the limitations of the testing scheme are clearly defined prior to metabolic workup.

This chapter draws extensively on a previously published work: Hoffmann GF, Nyhan WL, Zschocke J, Kahler SG, Mayatepek E (2002) Inherited Metabolic Diseases – Biochemical Studies. Lippincott Williams & Wilkins, Core Handbooks in Pediatrics, pp. 95–109. The authors acknowledge the use of that material.