This Week in Clinical Chemistry

In a review in Clinical Chemistry, Kristian Linnet from the University of Copenhagen and his colleagues discuss how to evaluate the accuracy of diagnostic tests. They write that prospective cohort studies are generally the best way to determine how well a test will perform in the clinic for the population for which it is intended, but they are not always practical or even possible. In that event, case-control studies could be designed to evaluate such tests. The authors also note that "the accuracy of a diagnostic index test is not constant but varies across different clinical contexts, disease spectrums, and even patient subgroups." Further, they add that "a diagnostic test should always be placed into a specific clinical context and its results judged on the basis of the diagnostic pathway in which it is to be used."

Jill Powlick, a patent attorney at Idaho Technology, discusses the Prometheus and Myriad patents in an opinion piece in Clinical Chemistry. "The question in both the Prometheus and Myriad cases is whether the claimed subject matter does substantially more than describe these laws of nature," she writes. The Supreme Court found that the Prometheus patents covered subject matter that was not patentable — "that the laws of nature are combined only with conventional activities that existed before the invention," she says. The ongoing Myriad case involving patents on the breast cancer genes BRCA1 and BRCA2 involves slightly different claims, and Powlick says "anything can still happen."