Scientists who developed the "nose" said it can show within 24 hours whether a patient's blood has bacteria that cause sepsis, a gain of up to two days over conventional methods.
"The current technology involves incubating blood samples in containers for 24-48 hours just to see if bacteria are present," said James Carey, a researcher at the National University of Kaohsiung in Taiwan.
"It takes another step and 24 hours or more to identify the kind of bacteria in order to select the right antibiotic to treat the patient. By then, the patient may be experiencing organ damage, or may be dead from sepsis."
Unveiled at a conference in Indianapolis of the American Chemical Society, the "nose" entails a palm-sized plastic bottle filled with a liquid nutrient that helps bacteria to grow.
Attached to the inside of the bottle is a small array of chemical dots that change color in reaction to the odors released by the telltale bacteria.
The new device can identify eight of the commonest disease-causing bacteria, Carey said in a press release issued by the American Chemical Society.
The device builds on a prototype developed a couple of years ago at the University of Illinois. The earlier model used lab dishes and a solid nutrient material to feed the bugs, which took longer and was less sensitive, the press release said.
Other work in an "artificial nose" has yielded prototypes that can detect forms of cancer in a patient's breath, and the presence of certain kinds of explosives.
Blood poisoning kills more than a quarter of a million people each year in the United States alone and inflicts treatment costs of more than $20 billion (15 billion euros) annually, according to figures cited in the presentation.
The device "can be used almost anywhere in the world for a very low cost and minimal training," said Carey.