Diagnostic patents and companies that rely on them to protect their businesses have suffered a lot of losses at the hands of the USPTO and the CAFC. While the jurisprudence around what is and isn't patent-eligible (101 eligibility) is ever-evolving, diagnostic patents (think methods of analyzing bodily fluids for specific components) have almost universally been deemed patent-ineligible and summarily invalidated. But, we just learned of some good news.
Illumina (of DNA sequencer fame) was able to successfully defend two of its diagnostic patents, US 9,580,751 and 9,738,931. These patents relate to preparing cell-free fetal DNA fractions from a blood sample taken from a pregnant woman in order to search for fetal chromosomal aberrations. It turns out that these fetal DNA fractions have fewer base pairs than the mother's DNA.
Illumina figured out a way to isolate this DNA and use it as a diagnostic test. That Illumina was able to successfully defend these patents is a good sign for the medical diagnostic industry. While this is only one data point, it does show that a novel and non-obvious method of preparing a DNA test fraction is patent-eligible. That's good news for medical diagnostic companies.