Introduction

Quantification of organic acid analysis is essential for management; it may also be important in diagnosis. For instance, the presence of hydroxyisovalerate, hydroxypropionate and methylcitrate may suggest a diagnosis of multiple carboxylase deficiency, but these compounds are also found in propionic acidemia. The two are readily distinguished by quantification. In multiple carboxylase deficiency the amounts of hydroxyisovalerate are large and those of the other compounds small, while in propionic acidemia, the reverse is found.