Direct-to-consumer genetic testing services are booming in popularity. This past “Black Friday” holiday shopping weekend, 23andMe spit-and-send test kits ranked among the top 5 best-sellers on Amazon, as we reported in our recent health care big data feature. But a new study published in the journal Nature raises a critical question: Just how accurate are these burgeoning at-home DNA tests (such as 23andMe and others), which may well influence consumers’ personal health decisions?

The study, led by Ambry Genetics—a more traditional clinical diagnostics company—suggests that up to 40% of examined “variants in a variety of genes reported in DTC raw data were false positives.” A rough translation? Some of these at-home tests may suggest users are at risk for a condition they’re not actually at risk for.

Ambry’s scientists’ research essentially suggests that clinical diagnostic companies offer a more clear picture of disease risk because they use a more comprehensive kind of genomic sequencing technology. And they emphasize that the possibility of false positives makes it critical for at-home kit customers to consult with a medical professional or genetic counselor before making any decisions about their health habits.

To be clear: regulatory agencies like the Food and Drug Administration gave blessing to 23andMe’s tests and accompanying health risk reports, concluding that the diagnostics were accurate enough and the reports clear enough that they can be marketed without a prescription.

DTC genetic test companies assert that their goal is to to empower patients. But others argue that such information requires a reliable, medical steward to confirm and properly interpret it. The debate about accuracy is one that’s likely to stick around.

Read on for the day’s news.

DIGITAL HEALTH

A national blockchain alliance for health care? In what may be a first-of-its-kind partnership, major health care organizations like Humana, UnitedHealthcare, Optum, and Quest Diagnostics are teaming up on a blockchain pilot program, according to Healthcare IT News. Blockchain, being one of those hot technologies whose underlying uses may appear mundane (but could prove quite significant!) may be used to "improve the quality of data and reduce the administrative costs associated with insurers getting up-to-date health care provider demographic data." If that sounds boring, you can read up on just how much better data use and management is already saving some health care systems money here. (Healthcare IT News)

INDICATIONS

Alkermes shares tank on FDA refusal letter. Biotech Alkermes' stock dropped nearly 23% in Monday trading following a regulatory hit from the Food and Drug Administration. The FDA issued a "refusal to file" letter for the company's application for an experimental depression drug, according to Alkermes, over insufficient evidence of its effectiveness. (NASDAQ)

THE BIG PICTURE

Medical marijuana and the opioid epidemic. A pair of new studies suggests that states with legal medical marijuana are associated with lower opioid abuse rates than others. (Obligatory reminder: Correlation does not equal causation.) The researchers, who studied Medicare data, "found a 14 percent reduction in opioid prescriptions in states that allow easy access to medical marijuana." (NPR)

REQUIRED READING

How DACA and the NAFTA Trade Deal Are Intertwined, by Grace Donnelly 

Why Donald Trump Is Really Taking Aim at Amazon, by David Z. Morris

Here's How Trump Is Expected to Retaliate Against China's New Tariffs, by Hallie Detrick

Apple Design Chief Jony Ive Talks What He Looks for In a New Hire and Steve Jobs, by Don Reisinger