Medical Emergencies · patient case question
Bence Jones protein testing is performed on which specimen?
Patient case: Bone pain, anemia and an enlarged tongue
Patient: 64-year-old man referred by his physician.
Chief complaint: His tongue feels too big for his mouth and he is exhausted.
History: Six months of back pain, fatigue and recurrent infections. Recent labs show anemia, hypercalcemia and elevated creatinine. Skull radiographs show multiple well-defined punched-out radiolucencies.
Findings: Enlarged tongue with lateral scalloping from tooth indentations. Pallor of the oral mucosa. Working diagnosis: multiple myeloma with systemic AL amyloidosis.
Show answer and explanation
Correct answer: C. Urine
- A. Serum protein electrophoresis detects the M-spike in blood, and the smear may show rouleaux, but Bence Jones protein specifically is a urine finding.
- B. CSF is not used in myeloma workup.
- C. CORRECT. Bence Jones proteins are free monoclonal immunoglobulin LIGHT CHAINS. They are small enough to pass the glomerulus and appear in the URINE, detected by urine protein electrophoresis and immunofixation. They are a major contributor to the renal failure of myeloma.
- D. Saliva has no role in the diagnosis.
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