Multitarget stool RNA test (ColoSense)

What it measures. Like the stool DNA test Cologuard, ColoSense combines a faecal immunochemical test for blood with molecular markers, but the molecular markers are eight messenger RNAs shed by colonic cells rather than DNA methylation and mutation markers. The rationale is that RNA levels change early in adenoma to cancer progression and are less affected by age-related methylation drift, which raises false positives in older people on DNA tests. The result is a single positive or negative call; a positive result leads to colonoscopy.

Evidence and regulatory status. In the CRC-PREVENT study of more than eight thousand average-risk adults, sensitivity for colorectal cancer was in the mid nineties per cent, sensitivity for advanced adenomas around 45 per cent, and specificity in the high eighties, in the same range as the multitarget stool DNA test. The FDA approved ColoSense in May 2024 for adults aged 45 and over at average risk. Its place in guidelines and its coverage in national programmes are still being settled; outside the United States it is not offered.

Who should have it and what changes. Anyone at average risk who is due for screening and will not have a colonoscopy has a choice between an annual faecal immunochemical test, a stool DNA or RNA test every three years, a blood test, or CT colonography. A positive stool RNA result should be followed by colonoscopy; a negative result means repeat in three years. The test costs several hundred dollars, more than a faecal immunochemical test, so its value depends on whether the extra sensitivity for cancer is worth the extra colonoscopies from false positives.