This study was aimed to explore the level of glycosylated ferritin in the patients with secondary hemophagocytic lymphohistiocytosis (HLH) and its diagnostic significance. 29 suspected HLH patients from October 2007 to October 2008 were enrolled in the study, and 25 healthy subjects were selected as control. The 29 suspected HLH patients were divided into confirmed group (22 out of 29) and unconfirmed group (7 out of 29) according to HLH-2004 diagnostic criteria. The percentage of glycosylated ferritin in peripheral blood was determined by phytohemagglutinin adsorption assay. The results showed that the median level of total serum ferritin in patients of confirmed group (2897.6+/-1837.2 microg/L) was significantly higher than that in patients of unconfirmed group (653.1+/-249.1 microg/L) (p<0.01), and was also higher than that in controls (414.6+/-212.6 microg/L) (p<0.01). The median percentage of glycosylated ferritin in patients of confirmed group was significantly lower (17.0+/-4.2%) than that in patients of unconfirmed group (40.7+/-4.5%) (p<0.01) and was lower than that in controls (53.6+/-13.3%) (p<0.01). The sensitivity (86.4% vs 77.3%) and specificity (71.4% vs 42.9%) of glycosylated ferritin for the diagnosis of HLH were higher than that of total serum ferritin. In conclusions, glycosylated ferritin may be a helpful marker for the diagnosis of HLH.