Do you expect your lab test to be reliable? Is it your belief that the results are a vital tool for the diagnosis of medical problems. Do you think that the FDA regulates all lab tests? If so, you need to know about lab-developed tests, or LDTs.
LDTs are diagnostic tests that are designed, manufactured and used solely within a single laboratory. They are not distributed or sold to any other labs or healthcare facilities to perform on their own. LDTs are often developed because a commercial test is not currently available. Some examples are certain cholesterol tests and genetic tests looking for Alzheimer’s risk or Huntington’s disease.
LDTs are not subject to strict FDA regulations the way other lab tests are. The FDA found that some of these tests failed to perform adequately, or worse, they caused harm. In an FDA report (November 2015), the FDA found, “We examined events involving 20 LDTs that illustrate, in the absence of compliance with FDA requirements, that these products may have caused or have caused actual harm to patients. In some cases, due to false-positive tests, patients were told they have conditions they do not really have, causing unnecessary distress and resulting in unneeded treatment. In other cases, the LDTs were prone to false-negative results, in which patients’ life-threatening diseases went undetected. As a result, patients failed to receive effective treatments.” These findings were sufficient to cause the FDA to consider regulation of LDTs.
In January 2017, the FDA put further regulation of LDTs on hold. They concluded, “Many stakeholders, in addition to FDA, have indicated that there is a public health need for greater oversight of LDTs…Extensive stakeholder feedback further confirmed the importance of balancing the unique qualities of LDTs, while still providing a reasonable assurance that such tests are analytically and clinically valid…”
In short, the FDA found the need but LDTs are still largely unregulated. If your doctor orders an LDT, discuss the pros and cons of this.