This is the fourth in a series of articles that describe how different types of laboratory tests are developed, validated, and made available for use by patients and their healthcare providers. This section deals with the types of tests for which the standard regulations are not practical or do not apply. These tests may be made available in special circumstances.
In certain cases, new or experimental laboratory tests may be made available to patients without FDA approval or regulation by CLIA. The use of such tests is considered exceptional; nevertheless, they are closely regulated by governmental, scientific, and professional entities.
The FDA's Humanitarian Device Exemption
In the United States, an exemption to Food and Drug Administration (FDA) regulations waives certain approval requirements for devices (including laboratory tests) for conditions diagnosed in less than 4,000 patients annually. Known as the humanitarian device exemption (HDE), it's intended to make the devices available to patients whose diseases are so rare that it would not be cost effective for manufacturers to conduct the required studies to get FDA approval.
Commercial laboratory tests — those produced and sold in volume to multiple laboratories — are categorized as devices and they receive FDA approval only after the developer or manufacturer submits research data showing the test is effective and useful. Manufacturers of tests falling under the HDE can sell the test kits without proving they are effective and useful. However, a manufacturer must still show that its exempted device does not pose a threat of illness or injury to patients and that the device's probable benefits outweigh risks.
FDA exemption as a Humanitarian Device means that the device is not fully proven to work. As such, it is treated as experimental. Any healthcare provider who wants to use a humanitarian use device must get institutional review board (IRB) approval before using that device to treat, diagnose, or monitor patients. The IRB is a committee that is formally designated to approve, monitor, and review medical research involving humans with the goal of protecting research subjects' rights and welfare. The IRB is responsible for initial and ongoing review of the humanitarian use device.
An example of a laboratory test exempted under the HDE is Mesomark, manufactured by Fujirebio Diagnostics. The FDA in January 2007 gave an exemption to Mesomark to measure the blood level of soluble mesothelin-related peptides (SMRP), protein fragments released into the blood by mesothelioma cells. Mesothelioma is a rare cancer of the membrane that covers and protects several organs as well as the chest and abdominal cavities. The approximately 2,000 to 3,000 U.S. patients diagnosed with mesothelioma annually usually have histories of working with asbestos.
The test is used to monitor patients diagnosed with malignant mesothelioma and is intended to add to the information from X-rays and imaging studies. Healthcare practitioners may order Mesomark to monitor mesothelioma's progression, recurrence, or response to therapy. Approved under the humanitarian device exemption, this test may give healthcare practitioners an additional tool for monitoring this rare but serious cancer.
Continue to the next article in the series: Part V: Tests Used in Clinical Trials