involved a transatlantic round-trip of ones and zeros: when the blood
test was completed, a cellular antenna on the reader beamed the
voltage data produced by the light signal to a server in Palo Alto. The
server analyzed the data and beamed back a final result to a cell phone
in Belgium. When the cellular connection was weak, the data
transmission would fail.
But there were other things besides the wireless connection that
could interfere with the generation of a result. Nearly all blood tests
require a certain amount of dilution to lower the concentration of
substances in the blood that can wreak havoc on the test. In the case of
chemiluminescent immunoassays—the class of tests the Edison
performed—diluting the blood was necessary to filter out its light-
absorbing pigments and other constituents that could interfere with
the emission of the light signal. The amount of dilution the Theranos
system required was greater than usual because of the small size of the
blood samples Elizabeth insisted on. For the reader to have enough
liquid to work with, the volume of the samples had to be increased
significantly. The only way to do that was to dilute the blood more.
And that in turn made the light signal weaker and harder to measure
precisely. Put simply, some dilution was good, but too much dilution
was bad.
The Edisons were also very sensitive to ambient temperature. To
function properly, they needed to run at exactly 34 degrees Celsius.
There were two 11-volt heaters built into the reader to try to maintain
that temperature when a blood test was being run. But in colder
settings, like certain hospitals in Europe, Dave Nelson had noticed that
the little heaters didn’t keep the readers warm enough.
Sunny didn’t know or understand any of this because he had no
background in medicine, much less laboratory science. Nor did he
have the patience to listen to the scientists’ explanations. It was easier
to just blame the cellular connection. Chelsea wasn’t much more
knowledgeable about the science than Sunny was, but she was friendly
with Gary Frenzel, the head of the chemistry team, and she gleaned
from their conversations that the difficulties went far beyond
connectivity issues.