A study published in the journal CANCER found that InSure,® a Fecal Immunochemical Test (FIT) from Quest Diagnostics Incorporated detected three times as many early- stage colorectal cancers and nearly two times as many significant (pre- cancerous) adenomas compared to Hemoccult II Sensa®(1), the traditional guaiac fecal occult blood test.(2)

In the study published in CANCER, individuals sampled consecutive stools, at home, to complete both the InSure and the Hemoccult II Sensa tests. Study groups included a screening cohort (n=2,351) and a symptomatic diagnostic cohort (n=161). Patients with positive screening results were referred for colonoscopy to detect possible cancer or a significant adenoma. Following colonoscopy, the cancer and type of polyp were subsequently confirmed by histopathology. The InSure FIT demonstrated a true-positive result significantly more often in the presence of cancer (n=24, 87.5% vs. 54.2%) or significant adenoma (n=61, 42.6% vs. 23.0%) than did Hemoccult II Sensa. Of all stage I cancers (where the tumor is limited to the lining of the bowel wall), the InSure FIT was positive in 12 of 13 cases, compared to only 4 of 13 with the Hemoccult II Sensa (p=0.002). The study results also showed that the InSure test is more capable than the Hemoccult II Sensa in detecting lower gastrointestinal bleeding in early-stage lesions or significant adenomas.

The InSure test had a marginally higher false-positive rate than did Hemoccult II Sensa (3.4% vs. 2.5%, respectively). This difference was due to detection of non-neoplastic pathologies, which when excluded the difference in false-positive rates became statistically insignificant (1.2% vs. 1.3%, respectively for the InSure and Hemoccult II Sensa tests).

"Early detection of significant adenomas and their removal should lead to a decrease in the number of people who will develop colorectal cancer," said Graeme P. Young, MD, FRACP, Professor of Gastroenterology, Department of Medicine, Flinders University of South Australia, where the study was conducted. "Importantly, this technology also has distinct behavioral advantages-people are more likely to complete and return the test owing to its simpler sampling procedure and reduced number of samplings."

Colorectal cancer is the second leading cause of cancer death in the United States. According to American Cancer Society (ACS) estimates, of the approximately 55,000 people expected to die from colorectal cancer this year, appropriate screening could save more than half. Patients with colorectal cancer detected in its earliest stage have a 90 percent chance of 5-year survival. ACS's latest guidelines for annual colorectal cancer screening include an option for an annual fecal immunochemical test or fecal occult blood test for people at average risk, 50 years of age and older.

"This is an important finding in the battle against colorectal cancer where early detection is critical," said Joyce G. Schwartz, MD, Vice President and Chief Laboratory Officer, Quest Diagnostics. "Since we began offering the InSure test, we've seen more doctors recommending it to patients, most likely because of the test's patient-friendly sample collection features."

About InSure

InSure FIT is a test that uses anti-human hemoglobin antibodies that are highly specific to human globin, the primary protein in blood that is released in stool when cancer and significant pre-cancerous adenomas are present in the colon and rectum. In contrast, guaiac-based fecal occult blood tests detect peroxidase activity of heme -- the part of hemoglobin that contains iron -- in feces; dietary peroxidases and heme from red meat may cause false positives.

Quest Diagnostics is the only laboratory to offer the InSure Fecal Immunochemical Test, an FDA-cleared test for use in screening for sources of lower gastrointestinal bleeding. The InSure test has features that increase the likelihood people will use the tests and return specimens. Among those features:

   -- No unpleasant fecal collection and smearing is required. The InSure
      test utilizes a patented long-handled brush to gently brush the
      surface of the stool and collect the surrounding toilet water to dab
      onto the collection card.  Whereas, the standard guaiac-based fecal
      occult blood test requires a wooden spatula collection of the stool
      sample that is completely clear of toilet water to be smeared on a
      test card.
   -- Only two specimens are required from consecutive bowel movements,
      compared to traditional Hemoccult II Sensa, which require six
      specimens from three bowel movements for analysis.

The study published in CANCER was funded by grants from the National Health and Medical Research Council of Australia and Enterix Australia Pty. Ltd. Enterix was acquired by Quest Diagnostics in September 2006. Neither company participated in the study's data analysis or influenced conclusions reached.

For more information on the study published in CANCER: http://www3.interscience.wiley.com/cgi-bin/fulltext/113348447/PDFSTART

For more information on colorectal cancer:

American Cancer Society http://www.cancer.org/docroot/CRI/content/CRI_2_6X_Colorectal_Cancer_Early_Det ection_10.asp

About Quest Diagnostics

Quest Diagnostics is the leading provider of diagnostic testing, information and services that patients and doctors need to make better healthcare decisions. The company offers the broadest access to diagnostic testing services through its national network of laboratories and patient service centers, and provides interpretive consultation through its extensive medical and scientific staff. Quest Diagnostics is a pioneer in developing innovative new diagnostic tests and advanced healthcare information technology solutions that help improve patient care. Additional company information is available at: http://www.questdiagnostics.com/.

The statements in this press release that are not historical facts or information may be forward-looking statements. These forward-looking statements involve risks and uncertainties that could cause actual results and outcomes to be materially different. Certain of these risks and uncertainties may include, but are not limited to, competitive environment, changes in government regulations, changing relationships with customers, payers, suppliers and strategic partners and other factors described in the Quest Diagnostics Incorporated 2005 Form 10-K and subsequent SEC filings.

  (1) Hemoccult II Sensa is a trademark of Beckman Coulter, Inc.

  (2) Smith, A., Young, G. et al.  Comparison of a brush-sampling fecal
      immunochemical test for hemoglobin with a sensitive guaiac-based fecal
      occult blood test in detection of colorectal neoplasia. Cancer 2006;
      107 (9) 2152-59.

SOURCE: Quest Diagnostics Incorporated

CONTACT: Jennifer Somers, Media, +1-201-393-5700, or Laure Park,
Investors, +1-201-393-5030, both of Quest Diagnostics

Web site: http://www.questdiagnostics.com/