A 70-year-old presents with bone pain, serum protein electrophoresis showing an M-protein spike of 4.2 g/dL (IgG kappa), serum free light chain ratio of 85, bone marrow plasma cells 65%, and lytic lesions on PET-CT. The International Staging System (R-ISS) staging uses which combination of parameters?

• A Serum albumin, creatinine, haemoglobin, and bone lesion count
• B M-protein size, CRAB criteria count, and plasma cell infiltration percentage
• C Beta-2 microglobulin alone with International Prognostic Index
• D Serum albumin, beta-2 microglobulin, LDH, and high-risk FISH cytogenetics ✓

Explanation

The Revised ISS (R-ISS) for multiple myeloma incorporates: serum beta-2 microglobulin, serum albumin (ISS components), LDH (elevated = high risk), and high-risk cytogenetics by FISH [del(17p), t(4;14), t(14;16)]. R-ISS I = ISS I + normal LDH + no high-risk cytogenetics; R-ISS III = ISS III + elevated LDH or high-risk cytogenetics. Creatinine and bone lesion count are part of CRAB criteria for defining active myeloma rather than prognosis staging.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.