In a comparative fungal blood culture study, a lysis-centrifugation system (Isolator; Du Pont Co., Wilmington, Del.) detected 89% of all episodes of fungemia; the lysis-centrifugation system detected fungemia exclusively or significantly earlier than did a biphasic brain heart infusion bottle system 83% of the time. The lysis-centrifugation system was particularly useful in the early detection of fungemia caused by Candida tropicalis and Candida glabrata. In 53% of the clinically significant episodes, the earlier detection was directly helpful in the management of patients with fungemia. High-magnitude candidemia (greater than 5 CFU/ml of blood) was significantly associated with the presence of an infected intravascular catheter and with Candida species other than Candida albicans. The lysis-centrifugation system was sensitive in the detection of fungemia during the monitoring of patients receiving antifungal agents or after removal of an infected intravascular catheter.