Sepsis is a systemic medical condition causing serious risk to health and life.This condition is most often diagnosed by culturing a specimen of patient blood or body fluid for bacteria.The health of patient populations in emerging economies would be aided by better diagnosis and treatment of sepsis. Unfortunately factors such as cost, ease of use, unreliable power and environmental control in laboratory facilities make automated blood culture untenable in these locations thereby limiting diagnostic options for clinicians.A comprehensive system design is proposed which addresses an unfulfilled need for an inexpensive method and apparatus which would facilitate automated blood culture. The design describes a disposable culture tube comprising a chemical sensor and bacterial growth medium.It also describes an automated instrument which will incubate, agitate, and optically interrogate culture tubes for evidence of bacterial growth. Culture tubes which demonstrate evidence of bacterial growth are reported as positive, facilitating the diagnosis of sepsis.