TDT’s blood test provides an extremely sensitive tool to monitor patients for recurrence of colorectal cancer. Since GC-C is only expressed on the surface of colorectal cancer cells when detected in the blood, it alerts physicians to the possibility of recurrent metastatic disease. If found, it gives the physician an early opportunity for intervention.

The GCC-B1™ blood test for surveillance of colon cancer is a major advancement in the science of monitoring colorectal cancer. Conventional monitoring employs the measurement of a protein called ‘Carcinoembryonic antigen’ or CEA that is associated with colon cancers as well as other types of tumors. The CEA immunoassay is known to have high rates of false positives and false negatives. In addition, other nonmalignant factors can affect CEA values such as cirrhosis, ulcerative colitis and even smoking.

In marked contrast, TDT’s blood test is highly sensitive and specific for the detection of guanylyl cyclase C (GC-C), which is expressed by colorectal cancer cells found outside the intestine. The GCC-B1 test detects a single cancer cell out of 10,000,000 normal cells.

The presence of GC-C in the blood may be an early indicator of micrometastases that would otherwise escape detection by the current standard of monitoring. Earlier detection provides an opportunity for more immediate treatment or surgical intervention to potentially improve patient outcomes and survival rates. Regular surveillance over a five-year period is critical since colorectal cancer has a recurrence rate of 43%.

Sample Collection

At present, GC-C Blood tests are performed only in TDT's clinical laboratories in Pennsylvania, and can be ordered only by physicians. TDT's scientists use a process called RT-PCR to amplify the molecular signal of GCC to determine if it is present in the sample.

Special kits have been developed to expedite the process of collecting and shipping patient samples to our laboratory for testing. A completed order form signed by both the patient and physician is required. Once the order form is received, the collection kit will be sent to the patient or a lab designated by the physician. The collection kit contains all of the materials, direction inserts and labels required for obtaining and return shipping the sample.

Physicians can download a form to fax or mail in the "Ordering A Test" section provided in this web site, or can call 800-431-0689.

IMPORTANT NOTE:
TDT is not a participating Medicare or Medicaid provider and does not bill either of these programs for the costs associated with these tests. TDT will provide the patient with the standard information required by insurance companies for reimbursement. The patient may elect to submit these materials and may receive full, partial or no reimbursement from his or her health care insurer. The patient must agree to assume full and direct responsibility for payment to TDT, Inc. for identified services. Subsequent reimbursement from any national or private insurance programs will be the patient's sole responsibility.