Many tests are used to assess proteins and other substances in the blood of multiple myeloma patients. These tests measure levels of blood calcium, total protein, serum beta-2 microglobulin, LDH, C-reactive protein, and blood glucose. They are used to monitor the disease and its potential complications.
These tests are part of a basic medical exam and are also very useful in diagnosing and monitoring myeloma.
Increased bone breakdown causes a higher than normal level of calcium in the blood (hypercalcemia). Hypercalcemia can cause kidney damage (see Tests to Assess Kidney Function). Bone-modifying agents can be used as treatment for hypercalcemia
Total blood protein testing measures all the proteins in the blood, which fall into one of two types, albumin and globulin.
Albumin is the most abundant protein in the blood. When myeloma is active, levels of a chemical messenger in the blood called interleukin-6 (IL-6) are elevated. IL-6 blocks production of albumin, so low albumin can signal more aggressive myeloma.
There are three types of globulin in the blood: alpha, beta, and gamma. Myeloma protein (M-protein) is a gamma globulin. If the myeloma cells are making M-protein, the amount of globulin in the blood rises, which results in elevated total protein. At diagnosis, elevated total protein should prompt your doctor to order more specific tests to see if you have myeloma.
Serum Beta-2 Microglobulin (B2M, β2M)
High serum beta-2 microglobulin indicates more active and aggressive myeloma. B2M is part of the IMWG Revised International Staging System for Myeloma, which helps to predict the potential for the spread and aggressiveness of newly diagnosed myeloma. In addition to its function in staging myeloma during the initial work-up, sβ2M can also be used to evaluate disease activity and to monitor response to treatment.
LDH (lactate dehydrogenase) is used in the revised staging system for multiple myeloma (R-ISS) to help determine prognosis. When tissues are damaged by injury or disease, blood levels of this enzyme are increased. LDH rises when myeloma is active.
C-reactive protein is produced in the liver. Elevated CRP is a marker of inflammation. CRP testing is probably used most commonly in the context of heart disease, but many diseases other than heart disease can cause increased CRP, including cancer. In a multiple myeloma patient, increased CRP can signal active disease.
Blood Glucose or Blood Sugar Test
The level of blood glucose (sugar) should be monitored carefully in all patients. Taking a steroid such as dexamethasone, an important component of treatment for myeloma, can raise the blood glucose level. If not monitored and controlled, elevated blood glucose can result in diabetes.