If you’re like most people, you’ve played the laboratory test waiting game, anticipating results that could tell if you have a serious illness or not. As if this wasn’t nerve wracking enough, federal regulators are now warning that results of laboratory developed tests may not be accurate.
An LDT is a diagnostic laboratory test that a single medical testing laboratory has designed and used to check for certain medical issues. These run the gamut from the most common complete blood count, also called CBC, to complex multigene panels.
If you’re like me, you’ve probably never questioned the test results, but you may change your mind after reading about some of the issues the Federal Drug Administration has raised.
Issues With Self-Regulation
LDTs are not required to undergo premarket review for safety and competency, the way medical devices and drugs are. There is no premarket review — and adverse event reporting isn't required, either.
That said, a recent Federal Drug Administration study looked at 20 common LDTs used to detect serious medical conditions, including ovarian and breast cancer, coronary heart disease, whooping cough, Lyme disease, fibromyalgia and fetal chromosomal abnormalities.
The study identified some important gaps including the following three issues:
1) False-positive results
The 20 LDTs that were red-flagged can cause patients harm due to false-positive results — when patients were told they have conditions they do not really have — causing unnecessary concern and treatment.
2) False-negative results
There were a significant number of false-negative results from the cited LTDs, in which patients’ life-threatening diseases go undetected and, as a result, untreated.
3) Lack of connection to the actual medical condition
Among the 20 questionable LDTs, some provided information with no proven relevance to the disease or condition for which they are intended for use. Still others are linked to treatments based on disproven scientific concepts.
How do you know your test results can be trusted? Ask your doctor. Your medical health professional orders tests for many patients every day, and dispenses medicine and other care based on test results.
It a lab sends tests that are wrong, the doctor should very quickly discover that the patient either didn’t get better, or got sicker. A lab producing low-quality work will be fired by the doctor, and replaced with a high quality lab.
The labs are required to maintain their own quality control.
According to the American Association for Clinical Chemistry, “once a laboratory has validated a test for in-house use, methods of quality assurance with regard to that test are carefully and continually followed by the laboratory.”
It’s up to the individual lab, then, to monitor the test to make sure results remain accurate and precise.
The Centers for Medicare & Medicaid Services regulates labs performing such tests through the Clinical Laboratory Improvement Amendments and state laboratory certification programs. Professional accrediting bodies also play a role in ensuring across-the-board quality.
While CLIA established requirements that are essential for ensuring that laboratories and their personnel maintain high quality standards, compliance with CLIA alone does not ensure that the diagnostic devices themselves are effective.
MedShadow Foundation, a nonprofit 501(c)(3) educates the public about the side effects and long-term effects of medication. MedShadow urges the FDA to have greater oversight of LDTs and address the concerns raised by their study to ensure safe, effective tests, and increase transparency of testing laboratories.
Ask Questions
In the wake of additional oversight by the FDA, consumers should ask more questions before agreeing to take diagnostic tests. Ask your doctor about the type of test being prescribed, and whether it has a record of accurate results.
If you or your doctor aren’t confident of the results, ask if another test from a different lab may be warranted. In addition, look online for information about the test and the reputation of the laboratory which analyzes the results.
Reviewed February 10, 2016
by Michele Blacksberg RN
Edited by Jody Smith