[srunni]

My biggest concern with Theranos, which I haven't really seen acknowledged in any of these articles, is that multiparametric panels on asymptomatic individuals will lead to a proliferation of false positives. Running hundreds of tests whenever a patient decides to do so doesn't make sense unless that ultimately enables better clinical outcomes for patients. And this is true regardless of whether the underlying measurement technology that Theranos has developed actually works or not.

It's discussed in a journal article from earlier this year by a pathologist:

> panel profiling, which was introduced in the 1970s as a way of identifying early biochemical changes of disease in asymptomatic individuals, had been abandoned in the 1980s, not so much for the cost. It has long been realized that with multiparametric testing, approximately 5% of results will be false positives, i.e., test results outside the reference intervals, in otherwise normal subjects. This is due to the definition of reference intervals, as being values between the 2.5 and 97.5 percentile of a reference (normal) population. The high cost of investigating seemingly abnormal results in normal people, and the added anxiety of patients, has led to the complete replacement of such biochemical profiling with what is now known as “discrete testing”. In the latter, tests are performed by the testing laboratory, only if requested specifically by the physician.

http://www.degruyter.com/view/j/cclm.2015.53.issue-7/cclm-20...

[robbiep]

This is a really valid criticism. I often send patients home from the emergency department with values outside of the normal, usually without discussing that finding with them (ie, it is not useful for a patient with some level of kidney failure to know that their sodium is 130, and has been on every presentation they have had for years). Trying to have a conversation with every second patient about why this value is slightly outside of reference and how the reference ranges are actually calculated is not productive and will likely only lead to confusion and obsfucation of the actual reason they presented

[yourapostasy]

The medical community should reconsider the standard policy of not having that conversation. While it may be medically sound practice, the insurance industry takes these reference values as Gospel Truth. Your life insurance premiums and coverage are predicated on how much deviation you exhibit from the reference ranges.

[robbiep]

Only in countries that are allowed to differentiate on the basis of lab tests. Which is not the case where I practice.

If a lab result is outside the normal range and a patient has a reason for it to be outside the normal range, that's fine. If a patient has a deviation that is related to their presenting complaint, that's fine too. If a patient has an unexplained deviation which is not related to the presenting complaint, well, there's a 1 in 20 chance that the variation is statistical only. So you use your clinical judgement. is this a patient who requires outpatient follow-up and repeat, or is this an abberation?

[martingoodson]

Actually, there is a one in twenty chance that a normal person would generate the results in question. Not the same thing.

[bane]

I have several people in my family who demonstrate various levels of hypochondriasis. Imagine the nonsense over gluten-free and every other fad diet of the last 30 years, non-specific symptoms, alternative "medicine" and that's two or three people in my immediate family. Now let them start ordering their own blood tests and it'll make the anti-vaxing movement look like a cultural blip.

Most people simply aren't smart or informed enough to understand things like "false positives".