Utility of Hemoccult Testing Before Therapeutic Anticoagulation in Venous Thromboembolism

Fecal occult blood testing (FOBT) is performed routinely before starting therapeutic anticoagulation in patients despite it never being validated to predict gastrointestinal bleeding (GIB) risk. Our objective was to determine the utility in checking the guaiac FOBT test (gFOBT) before initiating therapeutic anticoagulation in patients with a new diagnosis of venous thromboembolism (VTE).

This was a retrospective chart review that examined patients with a diagnosis of VTE admitted during a 2-year period in one mid-sized tertiary care center. The gFOBT was performed before initiating anticoagulation, excluding patients with overt GIB, and analysis was performed to determine GIB outcomes. In addition, demographics, laboratory data, and comorbidities were recorded at the time of admission, and an admission hypertension, abnormal renal/liver function, stroke history, GIB history or predisposition, labile international normalization ratio, elderly, drugs/alcohol concomitantly (HAS-BLED) score was recorded to determine other factors that were predictive of new-onset GIB when starting anticoagulation.

Initially, 718 patients with a new diagnosis of VTE were screened for 2 years. Ultimately, 375 patients were prescribed anticoagulation therapy and 244 had documented gFOBT. Of these 375, 14 (3.73%) had a GIB episode. A positive gFOBT was present on admission in 85.7% of those who bled (P < 0.001). The negative predictive value of gFOBT was 99.02%; however, the positive predictive value was only 30.77%. A HAS-BLED score >2 at admission significantly predicted GIB during admission as well (median 2.4 for those with GIB and 1.6 for those without GIB, P = 0.02).

Despite its beneficial negative predictive value, gFOBT before initiating therapeutic anticoagulation is unlikely to change the management of patients without evidence of overt GIB.