Abnormal Lactate Dehydrogenase Level Reduced Lactate Dehydrogenase Level The current label in HPO is "Reduced lactate dehydrogenase B level". Seems the "B" in the label and the comment that refers to the B subunit should be removed. Suggest update to label Decreased Lactate Dehydrogenase Level HP:0045041 A decreased or reduced level of the enzyme lactate dehydrogenase in serum.