The Food & Drug Administration (FDA) is warning that inaccurate, unreliable laboratory tests are harming patients when they are over-treated or under-treated for serious diseases like cancer.
Every year, between 7 billion and 10 billion laboratory tests are done in the United States. Even with an error rate below 0.1%, millions of people could get inaccurate results for a wide variety of medical and non-medical purposes, such as:
- Drug screening
- Blood work for life insurance
- Paternity testing
- Prenatal testing for genetic abnormalities
- Breast cancer gene mutation (HER2)
- And more
What is the problem?
The consequences of an inaccurate test result can be devastating. Patients who are diagnosed with illnesses they do not have may endure unnecessary medical treatment and expenses. Delayed diagnosis of serious illnesses like cancer can worsen prognosis.
Doctors sometimes fail to correctly diagnose a medical condition due to inaccurate results from laboratory tests. In some cases, the test itself is unreliable or diagnostic equipment is not used properly. Human error may also be to blame — samples got mixed up, results were misinterpreted, or the technician made a mistake during analysis.
FDA Warning: Inaccurate Tests Harming Patients
The FDA published a report (PDF) analyzing adverse events associated with 20 so-called “laboratory developed tests” (LDTs). “Patients have been demonstrable harmed or may have been harmed by tests that did not meet FDA requirements,” the FDA told Congress in November 2015.
LDTs are developed and used by a single laboratory for diagnostic testing. In the past, they were simple tests that were only used for rare diseases. Now, the industry is booming with tests for much more serious and common illnesses like cancer and heart disease.
How Could An Inaccurate Test Cause Harm?
- Treated with unnecessary medications
- Delayed diagnosis of underlying condition
- Added expense of treatment
- Unnecessary surgery to remove organs (ovaries, for example)
- Delay in appropriate treatment
- Cancer may progress
- Abortion of healthy pregnancy; birth of child with unanticipated genetic syndrome
- Patients receive inappropriate cancer treatment
- And more
Prenatal Tests Have High Failure Rate
When prenatal genetic testing is inaccurate, pregnant women may abort a healthy fetus or give birth to a baby with a severe genetic condition. Some tests have high failure rates, with false-positives rates of 50% or more.
Even so, companies are over-selling the accuracy of their tests and failing to warn about significant risks of false-alarms, according to an investigation by the Boston Globe.
HER2 Breast Cancer Test: Up to 20% False-Negative
Women who are HER2-positive who develop aggressive breast cancer should be on drugs that target HER2 receptors and improve survival rates. Most tests for HER2 are laboratory developed tests, but according to the FDA, they may be inaccurate:
“At least in the past, 20% of tests may have been inaccurate, creating concern that some invasive breast cancer patients may have been exposed to treatments that are less than optimal.”