FDA concerned over lab test loophole

The US Food and Drug Administration (FDA) is embarking on strengthening its regulatory oversight over medical laboratory testing, including so-called 'laboratory developed tests' (LDTs).

LDTs are diagnostic tests that have been developed and are performed in a single centralised laboratory. While the FDA reviews test systems or kits that are used in multiple hospitals, doctor’s offices, or laboratories, LDTs rarely undergo FDA review to ensure they are accurate, reliable, and provide clinically relevant results. Currently, labs that offer LDTs are only subject to regulations imposed by the Centers for Medicare & Medicaid Services (CMS) through the Clinical Laboratory Improvement Amendments (CLIA).

However, LDTs have increased in complexity and availability in recent years, and are now often used to diagnose common, serious medical conditions, including cancer and heart disease. Furthermore, a number of start-up companies have taken advantage of this loophole to develop tests that do not need to undergo regulation before being used on patients, some of which are directly marketed to consumers.

The FDA is therefore concerned about its lack of regulatory oversight and last year published draft guidance that proposes to phase in the enforcement of premarket review requirements for LDTs.

In order to help justify increased regulation of LDTs, the FDA have now published a report that outlines 20 examples of where LDTs have caused harm to patients, despite the labs offering them meeting the minimum requirements of CLIA.

In some cases, the LDTs were reported to provide false-positive results, which can cause patients distress, unnecessary treatments, and potentially delay the true diagnosis of a condition. Others were prone to false-negative results, which mean diseases can go undetected and untreated. Examples included breast cancer screening tests and a test to diagnose infection with human papillomavirus, a causative factor for cervical cancer.

Other LDTs were based on testing biomarkers with no proven relevance to the disease they are being used for, and the report also details the use of a prenatal test based on disproven scientific concepts.

The report also argues that patient safety is not the only problem arising from harmful LDTs, but that high financial costs (that exceed the cost of introducing FDA regulation) can be incurred when these tests give wrong results. The FDA estimated that the public-health cost associated with one harmful LDT – a test named 'CARE Clinical Autism Biomarkers Test' that led to the incorrect treatment of children – was $66.1 million (£44 million).

The publication of the report coincided with a hearing held in the US House of Representatives to discuss the FDA's draft guidance, and the roles the FDA and CMS should play in any new regulatory framework.

Jeffrey Shuren, director of the FDA’s Center for Devices and Radiological Health, told the hearing that the FDA wants to make sure that LDTs are 'accurate, reliable and that they do, in fact, identify a disease'. Some representatives, however, felt that CLIA oversight is sufficient, and criticised the FDA for only being able to detail 20 examples of LDTs causing harm.

The FDA plans to release the finalised guidance for the regulation of LDTs in 2016.