, Kim, , and Ryoo: False Positive Cases in Automated Blood Culture Systems Due to Hyperleukocytosis

Do-Hoon Kim1Namhee Ryoo1*

1Department of Laboratory Medicine, Keimyung University School of Medicine, Daegu, Korea

*Corresponding author: E-mail: nhryoo@dsmc.or.kr


Automated blood culture systems are widely used in clinical microbiology laboratories to minimize the workload of laboratory personnel and permit fast turnaround times. However, sometimes false positive signals occur due to leukocytosis, presence of fastidious bacteria, or unexplained causes. We experienced false positive signal in a patient with hyperleukocytosis for the first time since the automated blood culture system was introduced in our hospital over 20 years ago. We present two case reports with literature review and describe the procedure for dealing with false-positive cases in our hospital.


Figures & Tables


Fig. 1. Gram stain of initial blood culture of positive signal showed no bacteria, but with many WBCs (×1,000, left-first case; right-second case). WBC, white blood cell.