The Serum Lactobacillus Casei Folate Clearance Test in Various Hematologic Disorders.

F OLATE DEFICIENCY in man in the presence of normal serum vitamm B12 is presumed to exist with low serum folate levels,’ increased excretion of formininoglutamic acid2 or urocanic acid,3 megaloblastio anemia responding to physiologic doses of folic acid,4 and with a rapid clearance of folate from the serum following the injection of a small dose of folic acid.5 Of these tests the serum folate clearance is considered by some to be the most sensitive index of folic acid deficiency.#{176} With the use of the serum folate clearance test employing Streptococcus fecalis as the microorganism, folate deficiency has been reported in hemolytic anemias,7 neoplastic disease,5 cirrhosis of the liver,9 and following the use of anticonvulsant drugs.1#{176}