A physician-validated, board-style question from the Active Transport QBank. Try it, then check the reasoning for every option.
A 55-year-old woman with chronic hepatitis C and no significant family history presents with new-onset Raynaud phenomenon. She denies any recent infections or skin changes. Physical examination is notable for normal capillary refill and no ulcers. Laboratory studies show: serum creatinine 1.0 mg/dL, ANA negative, and a positive cryoglobulin test. Which of the following findings is most likely to be associated with her condition?
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A
Elevated serum ferritin levelsIncorrect. Ferritin elevation reflects inflammation or iron overload, not the complement-consumption pattern of HCV cryoglobulinemia.
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B
Low serum C3 complement levelsCorrect. HCV-associated mixed cryoglobulinemia consumes complement via immune complexes, producing characteristically low C3 and especially low C4.
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C
Positive anti-dsDNA antibodiesIncorrect. Anti-dsDNA antibodies are specific for SLE; the negative ANA here argues against lupus rather than cryoglobulinemia.
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D
High serum triglyceride levelsIncorrect. Hypertriglyceridemia is not a cryoglobulinemia feature; triglycerides are not driven up by immune complex disease.
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E
Increased serum calcium levelsIncorrect. Hypercalcemia is unrelated to cryoglobulinemia and points instead toward malignancy, granulomatous disease, or PTH disorders.
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Answer: B. This patient has features consistent with cryoglobulinemia due to hepatitis C, which is associated with low serum complement levels, particularly C3 and C4. Elevated ferritin, calcium, and triglycerides are not directly associated with cryoglobulinemia, and anti-dsDNA antibodies are more indicative of lupus.