This protocol is intended for use by external sites collecting clinical research specimens for T2 Biosystems' use in developing the T2Bacterial Assay. Specimens and information on patients' medical history, blood properties, medications, and blood culture history/results are required from the T2Bacterial Assay's target patient population (i.e., candidates for blood culture). Ideally, clinical specimens for use in developing the T2Bacterial Assay will be collected from negative blood culture, positive non-bacteria blood culture and positive bacteria blood culture patients.