By Nicholas Borgert

Wampole Laboratories’ new Clearview ULTRA FOB is a CLIA-waived rapid fecal occult blood test designed to be more patient- and technician-friendly than previous tests. Wampole anticipates the new screening could result in higher patient compliance than with the traditional guaiac-based tests.

The Clearview ULTRA FOB test from Wampole Laboratories.

This two-step immunoassay test for the detection of blood in the stool uses patented lateral flow and rapid membrane technology developed for Wampole Laboratories. The highly sensitive and specific test generates positive results in as soon as 1 minute, and negative results in 5 minutes, according to Jim DeAmbrose, product manager for Wampole’s point-of-care product line. To ensure a high degree of accuracy, the test has integrated procedural controls. The Clearview ULTRA FOB test is easier to use than traditional screenings that usually require patients to alter and restrict their diets in the days and hours before the test is performed.

Fecal occult blood tests (FOBTs)are among the most cost-efficient methods for detecting blood in a patient’s stool. Because cancerous tissue and precancerous polyps are more likely to bleed than normal colon tissue, the presence of fecal blood can serve as indicators of cancers of the colon or rectum. Blood in the stool may at times be the only symptom of colon cancer. A complicating factor is that polyps and cancers of the colon and rectum appear to grow slowly and may bleed only irregularly. Physicians depend on additional testing to determine the cause of the bleeding. Home screening for colon cancer does not replace the need for a regular examination by a health care professional.

Routine screening for fecal occult blood can have a significant impact on long-term health care costs. Studies reveal that among persons undergoing annual FOB screening, colorectal cancer mortality rates are 33% lower than mortality rates in those who are not screened. Incidences of colorectal cancer decrease by 20% among groups screened annually.

A negative result on a screening test does not rule out the possibility that a patient has colon cancer or polyps. The FOBT gives positive results in only 30%– 50% of the patients who have colon cancer. If an FOBT detects blood in the stool, additional tests, such as a rectal exam, colonoscopy, dual-contrast barium enema, or flexible sigmoidoscopy, are usually ordered by a physician.

A positive test result may be caused by a polyp, a precancerous polyp, or cancer. With a positive result, there is about a 5%–10% probability that a patient has early-stage colon cancer, even though half the time, no abnormality can be found to explain a positive FOBT result. Any screening test with a positive result should be followed up with another test for diagnostic purposes.

Facts About Colorectal Cancer

•    Colorectal cancer is the second leading cause of cancer deaths in the United States. At least nine in 10 cases of colorectal cancer occur in men and women 50 years of age and older.

•    Public health experts suggest that if everyone age 50 and over had regular colorectal cancer screenings, the mortality rate could be cut by one third or more.

•    In nearly every case, the cause of colorectal cancer can be traced to abnormal growths (precancerous polyps) that develop in the colon or rectum.

•    Screening in combination with other tests is an effective means of detecting colorectal cancer during its earliest stages when it is most treatable. Proper screening can help identify polyps so they can be removed before they advance to the cancerous stage.

Guaiac-Based Versus Immunochemical Tests
Traditionally, guaiac-based tests have been the dominant platform for fecal occult blood testing. But guaiac-based tests have shortcomings that cause problems for patients, physicians, and laboratories.

An immunochemical test (ICT) such as the Clearview ULTRA FOB test offers important benefits not associated with guaiac paper tests. The Clearview test is specific for human hemoglobin only. Its specificity and sensitivity improvements will result in fewer false-positive readings at a laboratory, and that translates into a reduction in the number of invasive procedures for patients. One study concluded that the cost of evaluating a false-positive test greatly influences which fecal occult blood test is best for screening. Decreasing the unnecessary procedures also serves as a cost savings for a medical facility.

Because guaiac-based tests are not specific for human hemoglobin, patients must change their diets prior to collection of their samples. For conventional fecal occult blood tests, patients have been required to follow strict dietary restrictions in the days leading up to the test. They must avoid eating any red meat for three days. Such foods as turnips, beets, radishes, horseradish, artichokes, mushrooms, broccoli, bean sprouts, cauliflower, apples, oranges, bananas, grapes, and melons can cause false-positive test results that indicate the presence of blood when there is none in the stool.

Other restricted substances include iron supplements, aspirin and nonsteroidal anti-inflammatory drugs, Vitamin C supplements, and such medications as colchicines, iodine, antacids, and boric acid. Dietary considerations during the screening process are a major concern with conventional fecal occult blood tests. These dietary restrictions are main factors that work against patient cooperation.

Unlike guaiac-based screenings, the Clearview ULTRA FOB test does not require patients to abide by pretest dietary restrictions. The test, which requires only one sample versus three with guaiac-based tests, provides results in 5 minutes with an easy-to-use dipstick format.

Statistics collected by the US Centers for Disease Control and Prevention (CDC) indicate that only 44% of all FOBT samples are returned by patients for testing and analysis. The CDC found that colorectal cancer claims fewer lives as early detection is improved.

Another shortcoming of traditional guaiac-based tests, says DeAmbrose, is that they are not specific for blood in the lower gastrointestinal (GI) tract. “It is that area where screening for colorectal cancer is targeted,” he says. “Often, guaiac tests will show positive for blood from any area in the GI tract, such as bleeding gums or an ulcer.”

The physician will determine which test is best for the patient, but the Clearview ULTRA FOB test is a more sensitive and specific screening tool than guaiac-based tests, and its features should lead to better patient care, according to DeAmbrose.

One recent study found that guaiac-based fecal occult blood tests performed in physicians’ offices may miss as many as 95% of potential cancers. The Clearview ULTRA FOB test is capable of detecting as few as 50 ng/mL of hemoglobin in fecal samples. Guaiac-based tests require many times more blood in the sample to result in a positive—some as high as 2,000 ng/mL of hemoglobin.

Because it is CLIA-waived, the Clearview ULTRA FOB test can be used in all settings, including hospital labs and physicians’ offices. For those who staff laboratories, the Clearview screen makes collection of the fecal sample easier and cleaner. With guaiac-based tests, the fecal sample is smeared on cards and returned to the lab. Patients unskilled at collection techniques can send back an excessive amount of sample and create a biohazard situation and unpleasant odor when a laboratory technician is processing the test. With the Clearview ULTRA FOB, a small sample is enclosed in a collection tube, reducing the opportunity for biohazard exposure and odor.

As an immunoassay test, the Clearview ULTRA FOB qualifies for the higher federal reimbursement. The 2004 national cap was $18.09; the reimbursement cap increased to $22.22 for 2005. The increase in reimbursement was in response to early-detection guidelines for colorectal cancer adopted by the American Cancer Society.

Wampole offers eight different configurations of its Clearview ULTRA FOB immunoassay, including test kits, controls, bottles, paper, and strips for sample collection. Because of the rapid testing turnaround, patients can obtain results on the same day the test is administered. The Clearview ULTRA FOB test can be stored at room temperature for up to 18 months before use.

Wampole Laboratories has also created a Web site for physicians and patients who want to learn more about colorectal cancer and fecal occult blood screening. Information can be found at www.clearviewfobt.com.     

Nicholas Borgert is a contributing writer for Clinical Lab Products.