Serum Vitamin B₁₂ in Leukemias and Malignant Lymphomas

High serum vitamin B₁₂ levels were found in chronic myeloid leukemia and in acute leukemia with myeloid differentiation. Following x-ray therapy and repeated blood transfusions, a drop of serum vitamin B₁₂ was found.

In chronic lymphatic leukemia, undifferentiated stem cell leukemia, Hodgkin’s disease, and multiple myeloma, the serum vitamin B₁₂ concentrations were normal.

In polycythemia with marked leukocytosis the serum B₁₂ was normal.

In myelosclerosis high B₁₂ values may be found.

The serum vitamin B₁₂ in chronic myeloid leukemia is in a bound form and the binding capacity for added B₁₂ is increased.

Serum vitamin B₁₂ determination may be of some value in differentiating various types of leukemia and other myelo-proliferative disorders.