Background: Because the testing for fecal occult blood (FOB) served as a non-invasive screening tool for
intestinal pathological conditions, we hypothesized that FOB might correlate with pathogenic Blastocystis
subtypes.
Objective: To evaluate the usefulness of FOB in blastocystosis as a marker of intestinal morbidity and its
correlation 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. pylori
antigens were performed, and Blastocystis strains were molecularly subtyped using the sequenced-tagged
site-based PCR assay.
Results: Among the study population, gastrointestinal (GI) symptoms were reported in 64.71%, including
abdominal pain (31.4%), diarrhea (13.7%), and irregular bowel habits (29.4%). Positive FOB was detected
in 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 alternating
bowel habits. No significant association was detected between FOB and any Blastocystis subtypes, or the
demographic and clinical parameters.
Conclusion: The study demonstrated FOB insignificant association with blastocystosis. Accordingly, we
eliminated its possible role as an intestinal morbidity marker in blastocystosis.