A 68-year-old man presents with pallor, bone pain, and hypercalcemia. Serum protein electrophoresis shows an M-spike of 4.2 g/dL (IgG kappa). Bone marrow biopsy shows 40% plasma cells. Serum creatinine is 2.4 mg/dL. According to CRAB criteria for multiple myeloma requiring therapy, how many CRAB features does this patient have?
- A 1
- B 2
- C 3 ✓
- D 4
Correct answer: C. 3
Explanation
CRAB criteria: C = hypercalcemia (>11 mg/dL or >1 mg/dL above upper normal), R = renal insufficiency (creatinine >2 mg/dL or CrCl <40 mL/min), A = anemia (Hb <10 g/dL or >2 g/dL below normal), B = bone lesions (lytic lesion, osteoporosis with fracture, or plasmacytoma). This patient has hypercalcemia (C), renal insufficiency — creatinine 2.4 mg/dL (R), and bone pain suggesting bone disease (B) — 3 CRAB features. Anemia was not specified as present, so we count 3 definite CRAB features.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.