EOL Tech Talk: Screening for Colorectal Cancer

Edition: March 2012 - Vol 20 Number 03
Article#: 3943
Author: Repertoire

In an age of medicine that focuses on better patient outcomes and reduced cost of care, screening for disease is critical. The earlier physicians detect and diagnose an illness, the more likely – and presumably the more precisely – they can treat it. Colorectal cancer is one of the most commonly diagnosed cancers and the third leading cause of cancer death for all Americans, according to the Centers for Disease Control and Prevention. And yet, a simple screening test is often all it takes to prevent the disease from developing.

One of the early warning signs of the disease is hidden (or occult) blood in the stool, which can be detected by a fecal occult blood test. For over 40 years, guaiac fecal occult blood tests (gFOBTs) have been available, which are based on the oxidation of guaiac by hydrogen peroxide to a blue-colored compound. A positive gFOBT may be due to bleeding in the upper and/or lower gastrointestinal tract and does not necessarily indicate colon cancer. In addition, gFOBT is not specific for human hemoglobin. Certain foods and medications can interfere with the accuracy of the test results.

Immunochemical fecal occult tests (IFOBT) – also called fecal immunochemical tests (FIT) – have been available for the last 14 years. They are said to be more sensitive and specific to human hemoglobin and do not involve the dietary or medicine restrictions indicated by guaiac tests. Although FITs do not detect upper gastrointestinal bleeding, they can be used to determine lower gastrointestinal bleeding indicative of colorectal cancer. FITs can also be used to screen for polyps, diverticulitis and colitis. In spite of the benefits to using FITs, some physicians continue to rely on digital rectal exams (DRE) to screen for colorectal cancer. However, medical guidelines warn against using DREs, as they tend to generate negative results, and some studies suggest these patients have nearly the same likelihood of having advanced neoplasia as patients who do not undergo any stool testing.

How the test works

Fecal immunochemical tests are antibody-based tests designed to screen for blood in the stool. They may be used to determine gastrointestinal bleeding found in several gastrointestinal disorders, including colorectal cancer, polyps, diverticulitis and colitis. Primary care physicians (e.g., internists, general practitioners and family physicians), gastroenterologists and OB/GYNs usually perform FITs as an annual screening in their offices, however the test also is used in laboratories and hospitals. Patients generally are screened beginning at age 50, unless they have a family history of a gastrointestinal disorder. The American Cancer Society Guidelines for the Early Detection of Colorectal Cancer recommends that patients also use the multiple-day stool take-home test, as one test performed in the physician’s office is not adequate.

The fecal immunochemical test is a one-step lateral flow chromatographic immunoassay test. Depending on the test, the patient generally takes a collection device home to collect his or her stool, and then returns the device to the physician’s office. The fecal sample is applied to a dry sample collection card, or it is suspended in a liquid and placed into a cassette for testing and results.

How to sell

A good number of physicians today continue to rely on traditional guaiac tests, and convincing them to switch to fecal immunochemical tests can sometimes present a challenge. True, FITs cost the physician more money upfront, but they offer greater clinical sensitivity and specificity and, as such, a valuable service to patients. In order for physicians to be reimbursed for either test, the patient must return the collection device with his or her stool sample. However, guaiac tests are associated with low reimbursement rates, and some doctors do not bother to file.

To successfully convert accounts from guaiac to FITs, sales reps should be prepared to discuss technology and performance, as well as reimbursement and costs. They should separate the patient take-home collection cost from the total cost of the test. In spite of the higher cost of FITs, reimbursement is significantly higher, making this option economically feasible. However, physicians are reimbursed only when the patient returns his or her sample and the development portion of the test is completed.

Reps should approach their physician customers with the following questions:

  • “How many patients at risk for colorectal cancer do you see each year?”


  • “How do you currently address colorectal cancer with these patients?”


  • “Are you interested in expanding your use of rapid tests?”


  • “Do you currently use guaiac tests or fecal immunochemical tests for colorectal cancer screening?”


  • “Are you aware of the benefits of fecal immunochemical tests?”


Reps should be prepared to educate their customers on variations in manufacturer recommendations. (In the past, some FITs have been FDA-cleared without indicating the number of samples required in the 510(k) documents.) In addition, they should educate customers about the American Cancer Society colorectal cancer screening guidelines.

In some cases physicians are under contract to refer their patients to a lab for fecal immunochemical testing. In general, however, many doctors can test in-house.

FITs have been reimbursable by Medicare since 2003. Reimbursement rates may vary by region or insurer.