Hepatic cirrhosis showing false-positive serum C-reactive protein reaction

A 58-year-old male who had been diagnosed as hepatic cirrhosis four years previously was admitted to our hospital because his serum C-reactive protein (CRP) level had gradually risen, reaching 139 mg/dl. No inflammation findings were observed subjectively or objectively. Close examination revealed his CRP reaction to be false positive. His serum CRP showed positive only in a latex agglutination method using goat anti-CRP IgG. This false-positive reaction was thought to be owing to the abnormally glycosylated IgM, which has an affinity for the goat serum IgG.