Beta-2 microglobulin Serum Test

Doctors order the B2M test as a follow-up test for people who have recently been diagnosed with multiple myeloma. This is done to assess the stage of the disease and evaluate the effectiveness of the treatment that is being given. It is also useful for determining the presence of tumours. 

Additionally, your doctor may order this test, along with a B2M urine test if you show the following signs of kidney damage:

• Presence of protein in urine
• Nausea
• Fatigue
• Weakness
• Bloody, brown or foamy urine
• Swelling around eyes or in the face, ankles or wrists

Since high Beta-2 microglobulin in urine indicates damage in the renal tubes (due to reduced B2M absorption through renal tubes), together, the two tests help find out the exact location of the damage.

(Health checkup app)

You do not require any special preparation for this test. 

Your doctor or a laboratory technician will use a sterile needle and withdraw a few milliliters of blood from a vein in your arm. He/she may tie a tourniquet over your upper arm first to locate the right vein - the tourniquet would make the vein to temporarily swell up so it becomes easier to put a needle in it. Sometimes, more than one needle insertion is required. Once enough blood is collected, the band will be removed from the arm.

You may feel a bit dizzy or lightheaded after the test or notice a bruise at the needle insertion site - they will go away on their own. 

Normal results:

The normal values for B2M in serum are between 1.21 and 2.70 mcg/mL. Low levels of B2M are considered to be normal. 

Abnormal results:

If there is an increase in the level of B2M in the blood then the results are considered to be abnormal. Serum B2M results may be elevated in benign conditions such as renal dysfunction, some viral infections or chronic inflammation. 

If the test was done to assess the cancer stage, the results will be evaluated accordingly. 

• In patients with multiple myeloma, serum B2M of <4 mcg/mL is indicative of a good prognosis.
• If the effectiveness of the treatment is being determined, then an increasing B2M level may mean that the cancer is spreading. Similarly, a drop in serum B2M level indicates that the treatment is working.
• If the serum B2M levels have neither increased nor decreased, then this may mean that the disease is stable.
• If the B2M levels decrease but later increase after cancer treatment, this may mean that the cancer has returned.

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.