Investigation of fecal occult blood as a marker of intestinal morbidity in blastocystosis

Background: Because the testing for fecal occult blood (FOB) served as a non-invasive screening tool forintestinal pathological conditions, we hypothesized that FOB might correlate with pathogenic Blastocystissubtypes.Objective: To evaluate the usefulness of FOB in blastocystosis as a marker of intestinal morbidity and itscorrelation with the detected subtypes.Patients and Methods: This cross-sectional study recruited 51 patients infected with Blastocystis spp.Demographic, clinical data, and stool samples were collected. Rapid diagnostic tests for FOB and H. pyloriantigens were performed, and Blastocystis strains were molecularly subtyped using the sequenced-taggedsite-based PCR assay.Results: Among the study population, gastrointestinal (GI) symptoms were reported in 64.71%, includingabdominal pain (31.4%), diarrhea (13.7%), and irregular bowel habits (29.4%). Positive FOB was detectedin 9 patients (17.6%). Two Blastocystis subtypes were identified: ST1 in 6 cases (11.8%), and ST3 in 45(88.2%). Statistical analysis indicated a significant association between Blastocystis ST1 and alternatingbowel habits. No significant association was detected between FOB and any Blastocystis subtypes, or thedemographic and clinical parameters.Conclusion: The study demonstrated FOB insignificant association with blastocystosis. Accordingly, weeliminated its possible role as an intestinal morbidity marker in blastocystosis.