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Our Tests Gut Health Assessment

Gastrointestinal Bleeding

Description/Background Information

Fecal occult blood is defined as the blood contained in feces that is hidden or not visibly apparent. It can be a late symptom of inflammatory mucosal damage to the intestine from multiple potential causes, including inflammatory bowel disease (Crohn’s disease or ulcerative colitis), diverticulitis, peptic ulcers, polyps, or colorectal cancer (CRC).1 Inflammatory bowel conditions may lead to CRC if left untreated.

Conventional methods used for the detection of fecal occult blood, including guaiac FOBT (gFOBT), do not provide a high degree of accuracy. Immunological tests developed to detect human hemoglobin [immunochemical FOBT (iFOBT) or fecal immunochemical test (FIT)] are more accurate and do not require special dietary restrictions for patients.2 An FOBT performed in the doctor’s office during digital rectal exam is not considered adequate for CRC screening.3 Salveo Diagnostics offers a high-sensitivity iFOBT kit with instructions for the patient on stool collection in the privacy of their own home and shipment back to the laboratory for analysis.

As the iFOBT does not indicate whether the blood is from the colon or other parts of the digestive tract, a positive result should be followed up with additional tests to determine the source of the bleeding. Although not all cancers or polyps bleed, early detection of gastrointestinal (GI) bleeding using the iFOBT may expedite follow-up colonoscopy/treatment and has been shown to significantly reduce mortality from CRC (Figure 1).2,4

Figure 1. iFOBT-based screening programs are associated with a significant reduction in deaths due to colorectal cancer.

Clinical Utility & Indications

Colorectal cancer is the third most common cancer and the third leading cause of cancer death in men and women in the United States (US).5,6 In fact, 1 in 20 people will be diagnosed with CRC in their lifetime. The American Cancer Society expects 134,490 new cases of CRC to be diagnosed in 2016—that’s 368 Americans every day—and 49,190 deaths from CRC (135 Americans every day).6

Risk factors for CRC include age (more than 90% of CRC cases are in people over the age of 50), family history (although 75% of CRC patients have no family history), and lifestyle choices (e.g., smoking, poor diet, inactivity, alcohol, and being overweight).5 Although incidence rates have been declining over recent decades (perhaps due to decreased smoking prevalence, increased use of anti-inflammatory drugs, and increased screening in those older than 50), the incidence in adults younger than 50 is on the rise.5,6

The iFOBT is recommended for annual CRC screening by the American Cancer Society-US Multi-Society Task Force (ACS-MSTF), the American College of Gastroenterology, and the US Preventive Services Task Force (USPSTF), for average-risk women and men aged 50 years and older.7-10 Individuals who are at higher risk of developing CRC (e.g., African-American ethnicity or family history) should begin screening at a younger age.7,10 If the disease is detected at an early stage, treatment is less extensive and more likely to be successful, with improved survival rates.4

The iFOBT is highly accurate for detecting CRC, with 86% sensitivity and 91% specificity—a higher sensitivity for detecting advanced colorectal neoplasias and cancer than the gFOBT, with an acceptable specificity that significantly reduces the need for colonoscopic evaluation in the screened population, i.e., a negative result indicates a very low likelihood of CRC being present.11-13 The lack of dietary or medicinal restrictions and the requirement of only a single stool sample (vs. three samples with the gFOBT) enhances patient compliance.2

iFOBT Cut Points and Interpretation

Negative Positive
< 100 ng Hb/mL ≥ 100 ng Hb/mL

 1. Bull-Henry K, et al. Am Fam Physician 2013;87(6):430–436.
2. Tinmouth J, et al. Gut 2015;64:1327–1337.
3. Young GP. Pract Gastroenterol 2004;28(6):46–56.
4. Zorzi M, et al. Gut 2015;64:784–790.
5. Siegel RL, et al. CA Cancer J Clin 2015;65(1):5–29.
6. American Cancer Society. Cancer Facts & Figures 2016. Atlanta: American Cancer Society; 2016.
7. Pignone M, Sox HC. Ann Intern Med 2008;149(9):680–682.
8. U.S. Preventive Services Task Force. Ann Intern Med 2008;149:627–637.
9. Levin B, et al. Gastroenterology 2008;134:1570–1595.
10. Rex DK, et al. Am J Gastroenterol 2009;104:739–750.
11. Van Rossum LG, et al. Gastroenterology 2008;135:82–90.
12. Lee JK, et al. Ann Intern Med 2014;160:171–181.
13. Johnson DA, et al. PLoS One 2014;9(6):e98238.

Why Gut Health?

Poor gut health is at the heart of many chronic conditions. A healthy gastrointestinal (GI) tract is vital to overall well-being and even survival. A recent explosion of scientific research worldwide, including the Human Microbiome Project (HMP), is providing new insights into the importance of the gut as the “gateway to good health” and giving new meaning to the phrase “you are what you eat.”

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