A study of 10,466 patients seen at an Iran hospital reports that patients with stool samples positive for Blastocystis infection were statistically more likely to have low serum iron levels. Additionally, occult blood was positive in 0.93% of Blastocystis-positive cases, and none of the control (p < 0.05). C-reactive protein was positive in 1.46% of the cases and 0.5% of controls. Erythrocyte sedimentation rate level was significantly higher in cases with Blastocystis infection as well (p < 0.05). The full free text is available from Przeglad Gastroenterology.