The pre-suit investigation has assumed greater importance in patent law with a series of appellate cases in the Court of Appeals for the Federal Circuit that resulted in the award of sanctions against parties who failed to conduct reasonable pre-suit investigations.

Under U.S. patent law, a party contemplating the filing of a patent-infringement suit must perform two steps before filing suit. First, the party must construe the claims in a reasonable manner. Second, the party must compare the construed claims to the accused device and make a reasonable determination that the accused device infringes the patent at issue. Often, this may require performing one or more physical, chemical, mechanical or electrical tests on the accused device.

In the case of a patent claim that covers an inexpensive consumer product that is readily accessible, it is relatively easy to conduct a pre-suit investigation. When the patent claim covers a process, an expensive product or a relatively inaccessible product, however, a party may have to rely upon a variety of pre-litigation tools or techniques, such as reverse engineering, testing, outside experts, literature review, patent documents, governmental and regulatory filings, court records, employment records, plant visits, trade shows, customers, suppliers or making direct contact with the accused infringer.

Reverse engineering and testing may be used to determine whether a product was produced by a particular process. A party can reverse engineer a particular process by performing various tests to find indicators that correspond to unique steps that make up the process.

It is not always possible to re-engineer a process. However, a party is required to do so whenever re-engineering is reasonable.

Outside experts are often helpful in conducting a pre-suit investigation because the experts can insulate the party or the attorney from the appearance of bias in conducting the investigation. An outside expert can also be used to verify that the party conducted the investigation.

A literature review can also be helpful. Companies often publish information about their products in technical journals, business journals or in their own marketing literature.

Patent documents may also be a source of information about a particular process. Such documents may include patents, patent applications, foreign patents or foreign applications.

A party may also be required to file documents relating to a particular process or product with a government agency, such as the FDA or the EPA. Such documents may also be helpful in conducting the pre-filing investigation.