Comparison of Microscopy and ELISA for the Detection of Entamoeba histolytica in Stool Samples of Pediatric Patients with Acute Gastroenteritis

Background: Amoebiasis caused by Entamoeba histolytica remains an important intestinal parasitic infection, particularly in developing countries. Conventional stool microscopy is inexpensive and widely available but has limitations in sensitivity and species-specific identification. Antigen-detection enzyme-linked immunosorbent assay (ELISA) provides an alternative diagnostic approach. Objective: To compare the diagnostic performance of conventional stool microscopy and ELISA for the detection of E. histolytica in stool samples obtained from pediatric patients presenting with acute gastroenteritis. Methods: A prospective observational study was conducted over a period of six months in the Department of Microbiology, SGT University, Gurugram, Haryana, India. A total of 79 stool samples from patients aged 1-18 years presenting with symptoms of acute gastroenteritis were examined. Direct wet-mount microscopy using normal saline and iodine preparations was performed for detection of Entamoeba cysts and trophozoites. All samples were additionally tested using the Serazym? Entamoeba histolytica ELISA, which detects the serine-rich E. histolytica protein (SREHP). Microscopy was used as the reference standard for calculation of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Results: Microscopy detected 2 positive samples (2.53%), whereas ELISA detected 3 positive samples (3.79%). Compared with microscopy, ELISA demonstrated a sensitivity of 100%, specificity of 98.7%, PPV of 66.7%, and NPV of 100%. One sample was positive by ELISA but negative by microscopy. Conclusion: In this study, ELISA demonstrated high diagnostic performance compared with conventional microscopy for the detection of E. histolytica. The additional ELISA-positive result highlights the potential value of antigen detection in samples that may not be identified by microscopy. However, the small number of positive cases and use of microscopy as the reference standard limit the precision and interpretation of the diagnostic accuracy estimates. Larger studies using an independent reference method are warranted.