A Comparative Study of Microscopy and Rapid Antigen Test for the Diagnosing Protozoan Diarrhea in Cancer Patients in Wasit Province, Iraq

Abstract

Background: Intestinal protozoal infections, particularly those caused by Entamoeba histolytica, Giardia lamblia, and Cryptosporidium parvum, pose serious health risks for immunocompromised individuals. Cancer patients are especially vulnerable, as these infections often lead to severe diarrhea and other gastrointestinal complications. Methods:  Stool samples were examined microscopically using direct smear and modified Ziehl–Neelsen staining. In addition, a rapid antigen test was performed to detect antigens of E. histolytica, G. lamblia, and C. parvum. Results: The overall detection rate of intestinal protozoal infections was significantly higher using the rapid antigen test (53.3%, 48/90) compared with microscopy (18.9%, 17/90). Based on the rapid test results, G. lamblia accounted for 43.75% of positive cases, C. parvum for 37.5%, and E. histolytica for 18.75%. The highest infection rates were observed among patients aged 41–56 and 57–72 years. A statistically significant association was found between age group and infection rate with both diagnostic methods (Microscopy: p = 0.041; RAT: p = 0.003). Participants were evenly distributed among breast, gastrointestinal, and hematological malignancies (33.3%) each. Participants were evenly distributed among breast, gastrointestinal, and hematological malignancies (33.3%) each. Conclusion: The rapid antigen test demonstrated greater sensitivity than microscopy for detecting intestinal protozoal infections in cancer patients. The high prevalence observed highlights the need for regular screening of this immunocompromised population. For rapid diagnosis and improved patient management, it is strongly recommended that rapid antigen testing be integrated into standard diagnostic protocols.