After this activity, the participant will recognize that fecal occult blood tests (FOBT) are validated only for colorectal cancer screening and asses the performance characteristics of FOBT in other clinical indications.
A 55-year-old woman is referred for further evaluation of iron deficiency anemia (IDA). She is post-menopausal, eats a regular diet including red meat, has no underlying medical conditions other than hypertension. She is currently on lisinopril and a multivitamin. She is not on any other medications or supplements, and denies taking aspirin or non-steroidal anti-inflammatory drugs. She denies any gastrointestinal symptoms including melena, hematochezia, nausea, or change in bowel habits. She has not had any operations. Her physical exam is unremarkable. Labs are remarkable for low hemoglobin with microcytic indices and low serum iron. She has had a negative fecal occult blood test (FOBT) collected from a spontaneous bowel movement.
What is the best next step in the evaluation of this patient?
- A. No further evaluation needed as FOBT was negative
- B. Start oral iron replacement without further evaluation
- C. Endoscopic evaluation including colonoscopy
- D. Repeat FOBT
A 22-year-old man with a 10-year history of ulcerative colitis and pancolitis presents with diarhea, about 7 stools per day. He is not having nocturnal diarrhea. He denies extraintestinal manifestation of inflammatory bowel disease. He feels this is not typical for a flare of his disease and he does not see blood in the stool. He reports compliance with mesalamine at 2.4 grams per day. He denies recent travel, fevers, chills, or abdominal pain. His last colonoscopy was 6 months ago and showed both endoscopic and histologic remission. A complete blood panel, C-reactive protien, and stool studies for enteric pathogens and calprotectin were done at the clinic. The clinic wants to do a FOBT on his stool sample.
According to this article, which one of the following statements is correct regarding the use of FOBT for this patient?
- A. This study found that FOBT–fecal immunohistochemical testing (FIT) has lower sensitivity and specificity compared to stool calprotectin for monitoring disease activity in ulcerative colitis.
- B. This study found good correlation between FOBT and stool calprotectin in predicting flare of ulcerative colitis.
- C. Multiple studies were available to compare the use of FOBT to stool culture in acute diarrhea and found good correlation in predicting flare of ulcerative colitis.
- D. This study found that FOBT was a good predictor of flares in ulcerative colitis and should be used as the primary tool to predict a flare of the disease.
According to this article, what percentage of patients with IDA would have an endoscopically identifiable cause of IDA, even though FOBT was negative?
- A. 17%
- B. 75%
- C. 58%
- D. 42%