A<unk>  is a medical laboratory test used to detect bacteria or fungi in a person's<unk> . Under normal conditions, the<unk>  does not contain microorganisms: their presence can indicate a<unk> stream infection such as bacteremia or fungemia, which in severe cases may result in sepsis.<unk> uring the<unk> , microbes can be identified and tested for resistance to antimicrobial drugs, which allows clinicians to provide an effective treatment. To perform the test,<unk>  is drawn into bottles containing a liquid formula that enhances microbial growth, called a<unk>  medium. Usually, two containers are collected during one draw, one of which is designed for aerobic organisms that require oxygen, and one of which is for anaerobic organisms, that do not. These two containers are referred to as a set of<unk> s. Two sets of<unk> s are sometimes collected from two different<unk>  draw sites. If an organism only appears in one of the two sets, it is more likely to represent contamination with skin flora than a true<unk> stream infection. False negative results can occur if the sample is collected after the person has received antimicrobial drugs or if the bottles are not filled with the recommended amount of<unk> . Some organisms do not grow well in<unk> s and require special techniques for detection. The containers are placed in an incubator for several days to allow the organisms to multiply. If microbial growth is detected, a Gram stain is conducted from the<unk>  bottle to confirm that organisms are present and provide preliminary information about their identity. The<unk>  is then subcultured, meaning it is streaked onto an agar plate to isolate microbial colonies for full identification and antimicrobial susceptibility testing. Because it is essential that<unk> stream infections are diagnosed and treated quickly, rapid testing methods have been developed using technologies like polymerase chain reaction and MALDI-TOF MS. Procedures for<unk> ng the<unk>  were published as early as the mid-19th century, but these techniques were labour-intensive and bore little resemblance to contemporary methods. Detection of microbial growth involved visual examination of the<unk>  bottles until automated<unk>  systems, which monitor gases produced by microbial metabolism, were introduced in the 1970s. In developed countries, manual<unk>  methods have largely been made obsolete by automated systems.
Blood culture
Sputum culture
Microbiological culture
Chest radiograph
Antibiotic sensitivity testing
Phonocardiogram
Coagulation testing
High-resolution computed tomography