- Blood testing using Theranos’ finger-prick technology was 1.6 times more likely to yield abnormal results, compared with standard venipuncture results from LabCorp and Quest Diagnostics, a study published in the Journal of Clinical Investigation found.
- Additionally, Theranos was 12.5 times more likely to say it could not obtain results from a sample.
- The study, which was conducted by Mt. Sinai researchers at the Icahn School of Medicine in New York City, was based on analysis of blood-testing results from 60 healthy adults across 22 different tests returned from three Phoenix, Arizona-based labs.
- Theranos has been critical of the Mt. Sinai study. Daniel Young, who heads up Theranos’ Arizona lab, and several other lab directors sent a letter to the researchers questioning the validity of the study’s results.
The researchers initiated the study four months before the Wall Street Journal’s bombshell investigative article alleged that the Palo Alto, CA-based Theranos had misrepresented its lab-testing businesses. They aimed to test inter-lab clinical equivalency and compare traditional venipuncture with Theranos’ fingerstick blood draw.
Joel Dudley, associate professor of genetics and genomic services at Mount Sinai, told the Washington Post: "In fact, our main motivation was it would be great to use the technology because low-volume blood draws would be an enabler of more regular testing.”
Significant inter-lab variability
But the researchers found significant variability between the results. Each of the 60 participants had 22 lab tests performed on samples taken by Theranos, LabCorp, and Quest. Among those 22 measurements, 15 showed significant interservice variability, including on white blood cell count and cholesterol tests.
According to the study, Theranos results had a noticeably higher rate of reporting measurements outside of their normal range at 12.2%, compared to 8.3% and 7.5% for LabCorp and Quest. From this, the researchers determined Theranos was 1.6 times more likely to report an abnormal result than the other two labs.
For example, lab results from Theranos for LDL and HDL cholesterol tended to report lower test values than those of LabCorp and Quest.
But, Theranos has taken issue with both the conduct and methodology of the study. In the letter sent to the researchers, Theranos lab directors highlighted “fundamental problems” which they believe “cast serious doubts on the validity of [the study’s] conclusions.”
They argue the rejection rate reported in the study (where Theranos was 12.5 times as likely to say it couldn’t obtain a sample) is unreliable because sample collection did not reflect normal procedure. The participants were tested using venous blood draws before going to a Theranos lab for a finger-prick test. Theranos says this could “negatively impact the quality of subsequent capillary blood collection.”
The lab directors also challenged the researchers’ reference methods for evaluating the tests.
Potential impact on health outcomes
In their JCI study, the researchers expressed concern the variant results could have a health impact. "While laboratory practice standards exist to control this variability, the disparities between testing services we observed could potentially alter clinical interpretation and health care utilization,” they wrote.
Since October 2015, Theranos has suffered a series of setbacks, including losing contracts with large clients. In late January, federal regulators at the Centers for Medicare and Medicaid Services (CMS) sent Theranos a letter warning that deficiencies at one of the company's laboratories in Newark, California posed "immediate jeopardy to patient health and safety." Theranos indicated it had responded to the concerns with a plan of correction earlier this month.
At this point, the only test Theranos is conducting with its finger-prick technology is for herpes. The company is also busily addressing the criticism that it has been facing for months and has emphasized its transparency. But the company has published no data in medical journals, according to Forbes. The study in JCI begins the process of comparing Theranos much-heralded technology with existing standards.