What is a Beta-2 Microglobulin test Why is it orderedWhat do the results mean

Beta-2 Microglobulin (β2M) is a small protein found on the surface of most cells in the body, especially white blood cells. It is normally filtered and removed by the kidneys, so elevated levels in the blood or urine may indicate kidney dysfunction, overactive immune activity, or certain types of cancer.In this guide from Daleeli Medical, we explain everything you need to know about the Beta-2 Microglobulin test — when it’s ordered, what the results mean, and how it helps in diagnosis and monitoring.

✅ What Is the Beta-2 Microglobulin Test?

The Beta-2 Microglobulin (β2M) test measures the level of this small protein in a blood or urine sample. It is used as a diagnostic and monitoring tool for conditions such as:

Kidney diseases
Certain cancers (e.g., multiple myeloma)
Autoimmune disorders
Monitoring chemotherapy or chronic illnesses

Why Is This Test Ordered?

1. Assessing Kidney Function

Since β2M is normally filtered by the kidneys, elevated levels may indicate impaired kidney function, even if other kidney tests (like creatinine) are still within range.

2. Diagnosing and Monitoring Cancer

Especially useful in conditions like:

Multiple Myeloma
Lymphoma
Leukemia

It is used as a tumor marker to track disease progression or response to treatment.

3. Evaluating Immune System Activity

β2M levels may rise in autoimmune diseases such as:

Systemic Lupus Erythematosus (SLE)
Rheumatoid Arthritis
HIV/AIDS

How Is the Test Performed?

Usually done using a blood and/or 24-hour urine sample
Fasting is not required
Let your doctor know about any medications you're taking before the test

Normal Reference Ranges for Beta-2 Microglobulin

Note: Ranges may vary slightly depending on the laboratory.

Sample Type	Normal Range
Blood	0.7 – 1.8 mg/L
Urine	Less than 300 µg/L

⚠️ What Do the Results Mean?

High Beta-2 Microglobulin Levels May Indicate:

Kidney damage (especially tubular dysfunction)
Multiple myeloma or leukemia
Chronic viral infections (e.g., HIV, CMV)
Autoimmune conditions
Organ transplant rejection

Low Beta-2 Microglobulin Levels

Generally not clinically significant, but may be seen in:

Good response to chemotherapy
Mild immunosuppression or malnutrition

Commonly Ordered Complementary Tests

Test	Purpose
Creatinine – eGFR	To assess kidney function
Serum Protein Electrophoresis	For detecting myeloma or blood cancers
CBC (Complete Blood Count)	To evaluate white/red blood cells
CRP – ESR	To detect inflammation
Bone Marrow Biopsy	If leukemia or bone marrow disorders are suspected

❓ Frequently Asked Questions (FAQ)

Does high Beta-2 Microglobulin always mean cancer?
No — it can also be elevated in kidney disease, immune disorders, or infections.

Is the test painful?
Not at all. It requires a regular blood sample or a 24-hour urine collection.

How long do the results take?
Typically 24 to 72 hours, depending on the lab.

✅ Summary

The Beta-2 Microglobulin test is a sensitive diagnostic tool used to evaluate kidney function, immune activity, and certain cancers. While elevated levels do not always indicate a serious condition, they are important markers that require further medical interpretation — especially when paired with other abnormal test results or symptoms.

If you're undergoing chemotherapy, or suffer from chronic immune or kidney issues, speak with your doctor to see if this test is appropriate for your condition.