There is evidence for the value of the following tests in the diagnosis, monitoring, and prognosis of myelomatosis: (1) serum paraprotein measurements, (2) urine paraprotein (including Bence Jones) measurements, (3) serum albumin, (4) serum urea, (5) proteins in the urine other than those in 2, and (6) hemoglobin level.
During treatment, increased rate of rise in 1 or 2, disproportionate increase in 2, emergence of related paraprotein, loss of 1 or 2 with reticulosarcomatous change, and monocytic leukemia suggest that more malignant subclones can emerge from the original myeloma clone, possibly due to drugs acting on DNA.
Hobbs JR. Monitoring Myelomatosis. Arch Intern Med. 1975;135(1):125–130. doi:10.1001/archinte.1975.00330010127016