Our multitarget stool DNA test (Cologuard) was developed using the principles of biology, chemistry and molecular biology. As a result, it is a powerful combination of technologies packaged into one convenient and highly effective precancer and cancer screening test.

In creating a stool DNA-based test, we sought to incorporate the most discriminating and informative biomarkers to ensure the highest possible sensitivity in detecting colorectal cancer. That is why the test includes a protein biomarker (hemoglobin), 7 distinct DNA point mutation biomarkers (KRAS gene), and 2 different DNA methylation biomarkers (NDRG4 and BMP3). One additional DNA biomarker (beta actin gene) confirms that the appropriate amount of stool DNA is analyzed in each individual sample. This multi-marker approach is a distinguishing feature of Exact Sciences’ scientific platform.

Innovation supports Cologuard’s scientific platform


Stool DNA Isolation

This proprietary technology proved to be a breakthrough in the development of the multitarget stool DNA test. Our scientists needed to first solve the essential problem of effectively isolating DNA from stool before achieving the goal of developing a noninvasive colon cancer screening test.


DNA stability technology

The development of an enhanced DNA stabilizing buffer was a critical step in the process of creating a reliable at-home screening kit. With this advance, the DNA in stool samples is protected through the transport process and remains amenable to analysis once it arrives at our processing center.


DNA biomarker detection

We developed our proprietary QuARTS technology (Quantitative Allele-specific Real-time Target and Signal Amplification) which efficiently amplifies and quantifies two separate methylated DNA markers (NDRG4 and BMP3) along with seven distinct KRAS gene point mutations. The beta actin (ACTB) gene serves as a reference marker for quantitation of the total amount of human DNA in each sample.

Hemoglobin Biomarker icon

Hemoglobin biomarker detection and stability technology

We improved upon the technology for the ELISA-based detection of a protein biomarker (hemoglobin) through an additive in the stabilization buffer. This innovation allows for longer transit time from sample collection to processing by the lab.


Powerful mathematical algorithm

The final step in the multitarget stool DNA test incorporates the quantitative results from the DNA alterations combined with the protein biomarker detection to determine a positive or negative result. This algorithm is the vital workhorse that translates our invisible biology into actionable information.