C90.00

HCC Category Mapping

What This Code Means

Multiple myeloma, a cancer of plasma cells in the bone marrow, that has not responded to treatment or is still active.

Coding Tips

• •Multiple myeloma is the most common type of immunoproliferative disease; fifth character indicates remission status
• •Document whether patient has achieved remission, is in relapse, or has not achieved remission for accurate coding

Clinical Significance

Multiple myeloma is the most common plasma cell neoplasm, characterized by malignant proliferation of plasma cells in the bone marrow producing monoclonal immunoglobulin that causes end-organ damage including renal failure, anemia, hypercalcemia, and lytic bone lesions (CRAB criteria). Non-remission status indicates the disease remains active and is causing or at risk for causing these complications. Multiple myeloma requires ongoing treatment to prevent disease progression and organ damage.

Documentation Requirements

• ✓Documentation must include bone marrow biopsy confirming plasma cell percentage, serum and urine protein electrophoresis with immunofixation, free light chain ratio, skeletal survey or PET-CT for bone lesions, and assessment of CRAB criteria.
• ✓Disease stage (ISS or R-ISS), treatment regimen, response assessment using IMWG criteria, and explicit non-remission status are required.

Commonly Confused Codes