Premium
Improving the performance of culture‐based bacterial screening by increasing the sample volume from 4 mL to 8 mL in aerobic culture bottles
Author(s) -
Souza Stephanie,
Bravo Marjorie,
Poulin Terri,
Vanderpool Sandra,
Kamel Hany,
Tomasulo Peter,
Su Leon L.
Publication year - 2012
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/j.1537-2995.2011.03489.x
Subject(s) - volume (thermodynamics) , confidence interval , apheresis , medicine , sample (material) , zoology , chromatography , chemistry , biology , platelet , physics , quantum mechanics
BACKGROUND: In the setting of bacterial detection of apheresis platelets (PLTs), the manufacturer recommended PLT inoculation volume for BacT/ALERT culture bottles (bioMérieux) ranges from 4 to 10 mL. This study compares the rate of capture of true‐positive (TP) contaminations between aerobic culture bottles inoculated with either 4 or 8 mL of sample and assesses if a larger sample volume reduces time to detection. STUDY DESIGN AND METHODS: Detection of TP samples and mean time to detection were compared for 4‐ and 8‐mL samples collected between September 1, 2003, and May 2, 2011. RESULTS: A total of 180,263 and 283,114 PLT collections were tested with an 8‐ and 4‐mL sample, respectively. Analysis of TP rates by volume sampled show an increase in the rate of detection of TP with the 8‐mL sample relative to the 4‐mL sample (139 vs. 106 per million events; odds ratio, 1.31; 95% confidence interval, 0.77‐2.23). Comparison of mean time to detection for TP shows a decrease in mean time to detection using 8 mL compared with 4 mL (12.36 ± 3.7 hr to 15.97 ± 6.3 hr, p = 0.012). CONCLUSION: Doubling the sample volume to 8 mL showed a trend in improvement for the rate of detection of TP and shortened the mean time of detection for TP by 23% when compared to a sample volume of 4 mL. The decrease in mean time to detection using a larger sample volume suggests that a shorter release time after inoculation could be achieved without significantly increasing patient risk.