Cytochemical identification of tetrahydrofolate in human leukocytes.

Utilizing the ability of molybdenum dioxide dichloride to form a black insoluble precipitate with tetrahydrofolate, a cytochemical test for rapid detection of tetrahydrofolate in human leukocytes was developed. The test may be useful in distinguishing deficiency of vitamin B12 or folate or both from other disorders of erythropoiesis characterized by megaloblastic erythropoiesis.