1Department of Nursing, Jinju Health College, Jinju, 2Medical Safety Division, Busan Regional Ministry of Food and Drug Safety, Busan, 3Department of Laboratory Medicine, Gyeongsang National University School of Medicine, Gyeongsang Health Science Institute, Jinju, Korea
Background: The pre-storage condition of blood culture bottles prior to entering the automated blood culture system may affect the time to detection (TTD) of microorganisms and the final report days.
Methods: We compared the TTD and final report days according to the pre-incubation conditions after laboratory operating hours: room temperature (RT) vs. a BacT/Alert unit (BioMerieux Inc.) for 3 months respectively. All bottles were inserted into the main BacT/Alert system the next morning.
Results: TTD was significantly reduced by pre-incubating bottles in a BacT/Alert unit (median, 8.4 h) compared to pre-storage at RT (median, 12.4 h) (P< 0.001). The final report of bacterial identification and drug susceptibility within 2 days was available for 24.4% of bottles pre-incubated in a BacT/Alert unit compared to 14.9% of those incubated at RT. The false positive results were significantly higher for pre-incubation in a BacT/Alert unit (0.81%) than for that (0.29%) at RT (P<0.001).
Conclusion: If a clinical microbiology laboratory is not operational for 24 hours, an automated blood culture unit might be a good alternative to reduce TTD and allow the submission of a faster final report compared to pre-storage at RT. However, false positive readings increased more than two-fold by pre-incubation in a BacT/Alert unit. (Ann Clin Microbiol 2014;17:105-109)
Keywords
Blood culture, Delayed entry, Detection time, False positive, Preincubation