A new final guidance document issued by the US Food and Drug Administration (FDA) aims to make it easier to develop in vitro diagnostic devices (IVDs) intended to act as microbiological or medical countermeasures.

The guidance document, Highly Multiplexed Microbiological/Medical Countermeasure In Vitro Nucleic Acid Based Diagnostic Devices, is specifically aimed at those IVDs which are intended to simultaneously detect 20 or more pathogens extracted from a single sample. Those IVDs, known as highly multiplexed diagnostic devices (HMDDs), are meant to test multiple targets "through a common process of specimen preparation, amplification and/or detection, and result interpretation," FDA explains in its guidance.

Such devices have great utility as medical countermeasures, especially when health professionals need to quickly determine which disease or pathogen might be affecting patients—and which are not.

While some of these devices are never given full approvals, and are instead given emergency use authorizations (EUAs) under the Pandemic and All-Hazards Preparedness and Reauthorization Act(PAHPRA), they are also approved under normal device review procedures as well. FDA's guidance is meant to explain the studies necessary to obtain market clearance [i.e. a 510(k) or de novo notification].

As with IVD's in general, FDA notes that HMDDs are not without risk. False positive results, false negative results, failure of the device to perform as indicated or improper interpretation of results can all present risks to human health. Such risks should be quantified and, to the extent possible, controlled.

FDA's guidance describes some of the basic elements of what each FDA application should include. For example, the guidance calls for companies to describe:

• a device's intended use
• the test methodology used by the device
• ancillary reagents used with (but not included with) the device
• device controls
• how to interpret test results

The guidance also contains an extensive section on performance characteristics, which should be established by properly designed studies. The section goes into the pre-analytical factors (such as specimen characteristics and quality controls), the analytical performance and specificity of the device, the precision and reproducibility of the device, the use of comparators, software used in the device, the design of clinical studies and the presentation of data.

The draft of the guidance document was published by FDA in November 2012.

Highly Multiplexed Microbiological/Medical Countermeasure In Vitro Nucleic Acid Based Diagnostic Devices (FR)