title: Sensitivity, but not specificity, of a quantitative immunochemical fecal occult blood test for neoplasia is slightly increased by the use of low-dose aspirin, NSAIDs, and anticoagulants.
abstract: OBJECTIVE
  We evaluated the effect of the use of aspirin, nonsteroidal anti-inflammatory drugs (NSAIDS), and anticoagulants on the performance of immunochemical fecal occult blood test (I-FOBT).
  
  
  METHODS
  A prospective, cross-sectional study of 1,221 ambulatory patients having total colonoscopy after preparing three I-FOBTs. Information regarding the use of medications was collected from the health medical organization (HMO) database. I-FOBT was analyzed with the OC-MICRO instrument using both >or=75 and 100 ngHb/ml of buffer thresholds to determine positivity.
  
  
  RESULTS
  Colorectal cancer (CRC) was found in 17 and advanced adenomatous polyp (AAP) in 97 patients. A total of 212 patients were using aspirin/NSAIDS at the time of I-FOBT testing. Qualitative analysis for the detection of AAP/CRC reveals a trend for an increased sensitivity with aspirin/NSAIDS use. At the threshold 75 ng/ml for positivity, the sensitivity for the detection of AAP/CRC was 66.7% for aspirin/NSAIDS use vs. 51.2% for nondrug takers (P=0.20), and at the threshold of 100 ng/ml, the sensitivity was 66.7 vs. 46.5% (P=0.09). The specificity, however, was not affected by the use of aspirin/NSAIDS. At the threshold of 75 ng/ml for positivity, the specificity for the detection of AAP/CRC was 89.5% for aspirin/NSAIDS use vs. 91.2% for nondrug takers (P=0.47), and at the threshold of 100 ng/ml, the specificity was 92.17 vs. 93.0% (P=0.69). A total of 33 patients were using antithrombotics/coagulants at the time of I-FOBT testing. This group was small; however, it appears that their use was also associated with a trend for increased sensitivity and no change in specificity.
  
  
  CONCLUSIONS
  The use of aspirin/NSAIDS and anticoagulants was associated with a trend for increased sensitivity with no change in specificity for the detection of AAP/CRC. This study suggests that there is no need to stop these agents before I-FOBT testing.
authors.affiliation: Department of Gastroenterology, Rabin Medical Center, Beilinson Campus, Petach Tikvah, Israel. zohar_levi@012.net.il
authors.forename: Zohar
authors.initials: Z
authors.lastname: Levi
authors.forename: Paul
authors.initials: P
authors.lastname: Rozen
authors.forename: Rachel
authors.initials: R
authors.lastname: Hazazi
authors.forename: Alex
authors.initials: A
authors.lastname: Vilkin
authors.forename: Amal
authors.initials: A
authors.lastname: Waked
authors.forename: Eran
authors.initials: E
authors.lastname: Maoz
authors.forename: Shlomo
authors.initials: S
authors.lastname: Birkenfeld
authors.forename: Nicky
authors.initials: N
authors.lastname: Lieberman
authors.forename: Shmuel
authors.initials: S
authors.lastname: Klang
authors.forename: Yaron
authors.initials: Y
authors.lastname: Niv
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects*; D000925:Anticoagulants / Q000009:adverse effects*; D001241:Aspirin / Q000009:adverse effects*; D003111:Colonic Polyps / Q000175:diagnosis*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D005260:Female; D006471:Gastrointestinal Hemorrhage / Q000139:chemically induced / Q000175:diagnosis*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008875:Middle Aged; D009780:Occult Blood; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000925:Anticoagulants; D001241:Aspirin