A recently published study about the accuracy of Theranos blood tests has raised some questions about its safety. Its finger blood tests produced more irregular results than conventional tests, a risk that could lead to misdiagnoses among patients.
The comparative tests were done in the U.S. two largest clinical laboratories, Quest Diagnostics and LabCorp. The medical start-up also came up with no answer at all for 2.2 percent of the measurements requested, a problem that did not occur with the lab’s tests, as reported by the New York Times.
However, not all the results of the study were negative for Theranos. Its measurements agreed with those of the other labs, and they were significantly less expensive. The few-blood-drops test cost only $33 for 22 measurements, about a fifth of the cost at the other two labs.
Theranos has used its test cost as a competitive advantage and said that it could perform numerous blood tests at a low cost while using just a few drops of blood from a finger, rather than the increased amount of blood taken in the conventional tests.
For the study, 60 healthy adults volunteers were tested twice in a day by Theranos and the other two medical laboratories. The team tested the volunteers for the 22 measures offered by the start-up, including various types of cholesterol and a complete blood count.
Most of the results were similar, but 12.2 percent of the measurements reported by Theranos were outside the expected normal range for healthy people, compared with 7.5 percent for Quest and 8.3 percent for LabCorp.
“There is actually pretty widespread variability in these clinical measures, even between the reference labs,” commented Eric Schadt, chairman of genetics and genomic sciences at the Icahn School and an author of the report. “But Theranos was more outside of range and outside of range in ways that would impact clinical decision-making,” he added.
The company’s reaction
Theranos sent a letter to the Journal of Clinical Investigation, in hopes to stop the study to be published. The letter was signed by the company’s directors and called the paper “flawed and inaccurate.” They expressed their disappointment for the fact that any journal would accept this study for publication.
Directors also claimed that just because a result was out the normal range did not mean it was wrong, and added that there was no attempt made by the study’s author to determine which measurement was correct.
However, experts on the field not related to the study said that this research was reasonably well done. Dr. Frederick L. Kiechle, medical director for clinical pathology at Memorial Healthcare System in Hollywood, said referring to the sent letter, that this represents just another effort for a failing company to cover up bad press for a technology that is not ready for “prime time.”
The differences among the patient’s measurements over cholesterol were qualified as “medically meaningful” and suggested that Theranos had not properly calibrated its tests to an industry standard, commented Greg Miller, professor of pathology and director of clinical chemistry at Virginia Commonwealth University.
Source: The New York Times