A patient reportedly went to the emergency room based on a blood test that Theranos had to retract

$4 has voided two years' worth of blood tests result from its flagship Edison machines, $4

Those Edison machines are Theranos' main claim to fame - CEO Elizabeth Holmes rose to prominence on the huge promise that with Edison, Theranos can test for blood-borne diseases with only a pinprick of blood from a fingertip.

But amid larger concerns over the $4, Theranos has told federal regulators that it's thrown out all results from 2014 and 2015.

That includes tests that Theranos did with Edison, as well as the ones it performed with traditional lab equipment, according to the Journal report. That means that anybody who got a Theranos blood test during that period may have gotten wrong results.

The Journal report indicates that physicians in Phoenix have gotten corrected results from Theranos in recent weeks. In fact, one patient went to the emergency room in 2014 based on a Theranos blood test result, says the report - a result that's now been amended.

The move to throw the test results out is a sign that Theranos is showing government agencies that it can regulate its own shortcomings. That's important, because $4, and it's trying to prevent further problems.

Theranos was not immediately available for comment.