2.3.3 Blood culture
Multiple blood culture samples should be taken from an aseptically prepared site in cases in which endocarditis is suspected. Ideally the samples are taken during the rising phase of a fever spike. Often this is not practicable; an alternative is to take daily samples for three days. A large volume of culture medium should be used. Both aerobic and anaerobic cultures should be submitted. Unfortunately, cultures are often negative; however, this does not rule out a diagnosis of endocarditis, or affect the prognosis. Successful culture means that appropriate antibiotics can be selected (see section 6.6.2).