Diagnostic Utility and Clinical Implications of Inpatient Fecal Occult Blood Testing

The objetive was to evaluate the utility of inpatient and emergency department (ED) fecal occult blood testing (FOBT) and its association with downstream healthcare utilization and costs.

This was a retrospective cohort study of adult patients (18 years and older) who underwent FOBT in the ED or inpatient setting at our tertiary academic hospital between April 1, 2020 and April 1, 2021. Patients with known colorectal malignancy were excluded. The data collected included FOBT indications, test positivity, gastroenterology consultations, endoscopic procedures, bleeding source identification, colorectal cancer (CRC) diagnoses, and cost analysis. Statistical analyses were performed using χ² and t tests, with significance set at P < 0.05.

In total, 826 patients were included, and 370 (45%) had a positive FOBT. Common indications were gastrointestinal bleed (60%) and anemia (22%). A bleeding source was identified in 43% of FOBT-positive versus 32% of FOBT-negative patients (P < 0.001). Positive results led to more gastroenterology consultations (72% vs. 33%, P < 0.001), esophagogastroduodenoscopies (36% vs. 10%, P < 0.001), and colonoscopies (15% vs. 7%, P < 0.001). CRC was diagnosed in 3% of FOBT-positive and 1% of FOBT-negative patients (P = 0.45). Mean cost per positive FOBT patient was $1185 versus $497 for negative FOBT.

FOBT use in the inpatient and ED settings has limited diagnostic yield for CRC or evaluation of gastrointestinal bleeding and is associated with significantly higher downstream healthcare utilization and cost. Institutional guidelines and decision support tools are needed to curtail inappropriate FOBT use and promote evidence-based care.