This test is used to screen the blood for the presence and identification of any pathogen (yeast, bacteria or other parasite). It is used for the diagnosis of septicemia (infection of blood). This test is also recommended for antibiotic susceptibility testing for different antibiotics for the selection of proper therapy. The symptoms that lead to recommendation of this test include increase in heartbeat, fever, nausea, increase in breathing and chills. This test is also used for the diagnoses of meningitis and endocarditis.