Data will be stored in an anonymized, encrypted, web-based patient registry. Bivariable analyses will be performed to identify and validate biomarker differences between groups. Furthermore, we intend to perform predictive modeling using multivariable analyses of the validated biomarkers and derive a biomarker panel and algorithm for early diagnosis of SS. The predictive value of the biomarker panel for early diagnosis of SS will be compared with established prognostic indices, such as metabolic endpoints and APACHE II score. Novel biomarkers of severe CAP will be identified by mass spectrometry of patient EDTA plasma samples. Subject to availability of multiplexed immunoassays, some of these biomarkers will be replicated by immunoassay in the same samples.