Formiminoglutamic acid
Formiminoglutamic acid is an intermediate in the catabolism of L-histidine to L-glutamic acid. It thus is also a biomarker for intracellular levels of folate. The FIGLU test is used to identify vitamin B12 deficiency, folate deficiency, and liver failure or liver disease. It is elevated with folate trapping, where it is accompanied by decreased methylmalonic acid, increased folate and a decrease in homocysteine.