Urinary Excretion of Formiminoglutamic Acid

Abstract

Folic acid deficiency results in inability to degrade a formiminoglutamic acid (FIGLU) to glutamic acid so that FIGLU accumulates in excessive amounts and is excreted in the urine. The assay technics which have been developed for detection of FIGLU are described and evaluated. Increased urinary FIGLU following an oral histidine monohydrochloride metabolic load of 15 g daily for two to three days is a biochemical index of folic acid deficiency. It is proposed as a new test to differentiate clinical folic acid deficiency states from those due to deficiency of vitamin B₁₂, such as addisonian pernicious anemia.