Yesterday the US Food and Drug Administration (FDA) issued a report on laboratory developed tests (LDT) – diagnostic tests that have been designed and manufactured for use in a single laboratory. According to the government agency, today’s LDTs are more complex, are used more frequently and have the potential to cause patient harm if not properly administered.
The FDA first began to regulate the development and manufacture of medical devices in the 1970s, under the Medical Device Amendments of the time. The agency originally decided not to regulate LDTs due to their simplistic nature and the fact that they were often only used to diagnose rare conditions.
The FDA’s decision to increase oversight over the production of LDTs comes following the development and application of increasingly complex tests, which are now often used to diagnose serious diseases including heart disease and cancer. Currently, these LDTs still fall under discretionary enforcement of medical device regulations and as such, these diagnostic tools have rarely been assessed by the FDA to confirm reliability, accuracy and meaningfulness of results.
This lack of FDA oversight means that issues associated with LDTs are rarely reported to the agency’s adverse event databases. Despite the lack of data, the FDA was able to collect data from the public domain on 20 different case studies demonstrating the problems associated with LDTs, which could be a product of the lack of regulatory agency oversight.
For example, some LDTs have been found to provide false positives resulting in significant patient harm. The FDA cites a diagnostic tool used to test for the bacteria that causes Lyme disease; if the test gives a false positive, the patient may be given unnecessary treatment which could, in turn, prolong the time it takes to give the patient an accurate diagnosis. The agency points out that the occurrence of false positives could have an even more harmful effect on patient wellbeing if a women was diagnosed with ovarian cancer – based on the results of an LDT – resulting in the decision to have her ovaries removed.
Another problem with some LDTs is the risk that the test could produce a false negative. During the FDA’s review of the case studies, they came across a test designed to measure levels of human epidermal growth factor receptor 2 (HER2) – a protein that enhances growth of breast cancer cells – and found that approximately 20 percent of the LDTs may have produced inaccurate results. As patients expressing high levels of HER2 are often prescribed drugs to target the protein in complement to chemotherapy treatment, these false positives may have prevented breast cancer patients from receiving the best treatment available.
In the case of Noninvasive Prenatal Testing, LDTs are used to detect a number of fetal genetic abnormalities, and there is a risk that the test could produce a false positive or a false negative. Women who receive a false positive result may decide to terminate their pregnancy, while those receiving a false negative may be unprepared when they give birth to a child with a genetic syndrome.
The FDA also notes that some tests investigated were found to demonstrate no clear relation to the disease being tested, while others are based on antiquated scientific concepts. In addition to the costs to patient health, the financial burden on public health resulting from a lack of regulatory control over LDTs is significant. Economists at the FDA estimate the total public health cost for one of the potentially faulty tests – the CARE Clinical Autism Biomarkers Test – is $66.1 million.
In light of this new evidence regarding the safety of LDTs, the FDA has proposed an increase in oversight of the tests. The agency is working towards finalizing guidance proposing enforcement of premarket review requirements for LDTs – a report that was originally drafted in 2014. The hope is that this increased regulatory control would ensure only tests based on sound scientific evidence, providing clinically accurate test results, would be used to ensure minimum risk of patient harm.
- Why FDA Should Oversee Laboratory Developed Tests – http://blogs.fda.gov/fdavoice/index.php/2015/11/why-fda-should-oversee-laboratory-developed-tests/
- The Public Health Evidence for FDA Oversight of Laboratory Developed Tests: 20 Case Studies – http://www.fda.gov/AboutFDA/ReportsManualsForms/Reports/ucm472773.htm