A 62-year-old man presents with painless obstructive jaundice. CT shows a mass in the head of the pancreas and total bilirubin is 14 mg/dL. His CA 19-9 level is reported as 850 U/mL. Which statement correctly guides the interpretation of this result?
- A Obstructive jaundice itself causes false elevation of CA 19-9, so the result cannot be interpreted until biliary drainage is achieved ✓
- B The value confirms unresectable metastatic disease and precludes surgery
- C CA 19-9 is unreliable only in patients who are Lewis antigen negative
- D CA 19-9 above 500 U/mL excludes resectable disease regardless of imaging
Correct answer: A. Obstructive jaundice itself causes false elevation of CA 19-9, so the result cannot be interpreted until biliary drainage is achieved
Explanation
Cholestasis from any cause, including benign biliary obstruction and cholangitis, markedly elevates CA 19-9, so the marker should be interpreted only after biliary decompression normalizes bilirubin. Option B and D wrongly convert a marker into a resectability decision, which rests on cross-sectional imaging. Lewis antigen negativity is a real limitation of CA 19-9 but is a separate issue and does not apply to this patient.
Reference: Sabiston Textbook of Surgery, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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