Metabolic, nutritional, iatrogenic, and artifactual sources of urinary organic acids: a comprehensive table.

BACKGROUND: The determination of organic acids and glycine conjugates in urine is key for the diagnosis and follow-up of several inborn errors of metabolism (IEM). However, clinical interpretations may still be hindered by ambiguity in the sources of some urinary organic acids and acylglycines as well as in the relationship between their excretion and IEM. APPROACH: Relevant data have been compiled from major books and references on the topic and by exhaustive bibliographic searches through the Medline and Current Contents databases. CONTENT: A comprehensive table has been designed according to organic acids and conjugates. This table is intended to assist in the interpretation of organic acid profiles because, in addition to IEM, it also refers to other pathologic causes and to physiologic, nutritional, iatrogenic, and artifactual sources. Some preanalytical issues, including possible misinterpretations, are reviewed with regard to IEM.