BETA-2-MICROGLOBULIN

Test Code

B2M

CPT Codes
82232

Preferred Specimen

PLASMA

Transport Container

LIGHT GREEN

Transport Temperature

Refrigerated

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Hemolyzed specimens; lipemic specimens

Clinical Significance

Beta-2-microglobulin normally passes through the glomerulus into the proximal tubule where much of it is reabsorbed. Serum levels are therefore an index of glomerular function. When impaired, serum levels rise in inverse ratio to glomerular filtration rate. Increased amounts of beta-2-microglobulin are excreted in several renal disorders, e.g., Balkan nephropathy, heavy metal poisoning and renal tubular disease due to therapeutic agents. Serial levels of beta-2-microglobulin in serum and urine are used to evaluate transplant viability and anticipate rejection. Following a successful graft, serum levels decline toward normal. Increasing serum levels provide an early sign of rejection. Elevated levels are also noted in lymphproliferative disorders, neoplasms (malignant and benign), inflammatory disease, and autoimmune diseases such as systemic lupus erythematosus (SLE) and Sjögren's disease.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.