Multitarget stool DNA TEST (Cologuard)

A noninvasive stool-based DNA test for the detection of colorectal cancer (CRC) in asymptomatic individuals at average risk, demonstrating superiority to the fecal immunochemical test (FIT).

The test includes DNA molecular assays for DNA mutation and methylation biomarkers associated with colorectal neoplasia KRAS mutations and NDRG4 and BMP3 methylation and a non-DNA immunochemical assay for human hemoglobin it is almost identical to the assay used in FIT’s.

Contains a reference Gene beta-actin to estimate the total amount of human DNA present in each sample.

Cologuard detected CRC in 92% of patients compared with 74% with FIT screening.

Advanced adenomas were detected in 42% of patients with Cologuard compared with 24% with FIT.

The most sensitive FDA approved noninvasive screening test for colorectal cancer is the mt-sDNA test (Cologuard): 92% sensitivity for colorectal cancer in patients 50 years and older, and 42% for advanced adenomas.

The Cologuard test uses quantitative molecular assays for KRAS mutations, abnormalities in methylated BMP3, NDRG4, and β-actin along with a hemoglobin immunoassay.

The result of the assay of the mutation, methylation and hemoglobin are combined to produce a composite score compared to a cut off value to determine a positive or negative effect.

The initial study enrolled 12,776 participants at average risk for CRC, with 9989 meeting the criteria for evaluation.

All individuals in the study underwent a colonoscopy and screening with FIT and Cologuard: By colonoscopy, 65 participants had CRC and 757 had precancerous lesions.

The sensitivity for detecting CRC in the 9989 eligible patients was 92.3% with Cologuard compared with 73.8% with FIT.

Cologuard detected 42.4% of advanced precancerous lesions compared with 23.8% with FIT.

For high-grade dysplasia and sessile s2242ate polyps, Cologuard detected 69.2% and 42.4% compared with FIT 46.2% and 5.1%, respectively.

Cologuard detected 13 of 60 screening-relevant (stage I-III) cancers that were undetected by FIT compared with 1 cancer detected by FIT that was not found with DNA testing.

For patients who tested negative for CRC and advanced precancerous lesions (n = 9167), Cologuard detected 86.6%, representing a false positive rate of 13.4%, and FIT detected 94.9% of negative findings, for a false positive rate of 5.1%.

The test requires the patient to collect a single stool sample without dietary or medication restrictions.

The test is shipped to the patients home to collect a stool sample.

There is a separate tube for collection of part of the sample for hemoglobin testing, bottle of liquid preservatives putting the sample container there is a shipping box and labels.

A negative result gives 99.94% assurance that the patient does not have cancer and 94.79% chance the patient does not have an advanced adenoma.

The next generation multitarget stool, DNA test, showed higher sensitivity for colorectal cancer and advanced pre-cancerous lesions then FIT but also showed lower specificity (Blue-C study investigators).

Testing should be done every three years, and the cost of the test is $649.

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