Replies to post #160039 on Biotech Values

[DewDiligence]

EXAS—Low sensitivity can be conquered by repeating the test frequently, which is not a major imposition given that the test is non-invasive. I.e., the cumulative sensitivity of a series of tests over a multi-year period can be made to be acceptably high.

However, as a practical matter, you cannot market a screening test that produces dozens of false positives for each true positive, which is what happens when the specificity of the test is low and the rate of disease in the underlying population is also low.

I’m on my way out, but I’ll provide some arithmetic later.

[DewDiligence]

EXAS—Colon Cancer Alliance blasts USPSTF’s evaluation of Cologuard:

http://www.prnewswire.com/news-releases/colon-cancer-alliance-us-preventive-services-task-force-recommendations-300157279.html

My contemporaneous (2013) view on this matter (#msg-86983487) was that Cologuard's 87% specificity could be a problem vis-à-vis commercial uptake, and that turned out to be a pretty good call.

However, USPSTF has gone too far, IMO, by improperly defining the test's specificity (#msg-117515504) and failing to take into account the test’s 3-year interval, thereby relegating Cologuard to “alternative” rather than “recommended” status. Thus, I find the arguments in the CCA’s PR (linked above) to be valid.