Blood culture quality and turnaround time of clinical microbiology laboratories in Chinese Teaching Hospitals: A multicenter study

Abstract

Purpose: Blood culture (BC) remains the gold standard for the diagnosis of bloodstream infections. Improving the quality of clinical BC samples, optimizing BC performance, and accelerating antimicrobial susceptibility test (AST) results are essential for the early detection of bloodstream infections and specific treatments.

Methods: We conducted a retrospective multicenter study using 450,845 BC specimens from clinical laboratories obtained from 19 teaching hospitals between 1 January 2021 and 31 December 2021. We evaluated key performance indicators (KPIs), turnaround times (TATs), and frequency distributions of processing in BC specimens. We also evaluated the AST results of clinically significant isolates for four different laboratory workflow styles.

Results: Across the 10 common bacterial isolates (n = 16,865) and yeast isolates (n = 1011), the overall median (interquartile range) TATs of AST results were 2.67 (2.05-3.31) and 3.73 (2.98-4.64) days, respectively. The specimen collections mainly occurred between 06:00 and 24:00, and specimen reception and loadings mainly between 08:00 and 24:00. Based on the laboratory workflows of the BCs, 16 of the 19 hospitals were divided into four groups. Time to results (TTRs) from specimen collection to the AST reports were 2.35 (1.95-3.06), 2.61 (1.98-3.32), 2.99 (2.60-3.87), and 3.25 (2.80-3.98) days for groups I, II, III, and IV, respectively.

Conclusion: This study shows the related BC KPIs and workflows in different Chinese hospitals, suggesting that laboratory workflow optimization can play important roles in shortening time to AST reports and initiation of appropriate timely treatment.

Keywords: blood culture; clinical microbiology laboratory; key performance indicators; laboratory workflow; turnaround time.

FIGURE 1

Monitoring of key performance indicators for blood culture in 19 hospitals. The abscissa represents the numbers of beds that were arranged from large to small. The blue curve represents the positive rate of BCs in 19 hospitals. The pie chart represents the percentages of bottles and sets of BCs. Y axis on the left means the number of blood cultures. Y axis on the right means the positive rates. BC, blood culture specimens.

FIGURE 2

Hourly frequency distributions of pre‐analytical times in blood culture specimens. (A) Hourly frequency distributions of specimen collection, reception, and loading times. (B) Box‐and‐whisker diagram of distributions for turnaround times from blood specimen collection to laboratory reception. (C) Box‐and‐whisker diagram of distributions for turnaround times from blood specimen reception to culture loading. (D) Box‐and‐whisker diagram of distributions for turnaround times from blood specimen collection to culture loading. The horizontal lines within the boxes indicate the median turnaround times. The boxes denote the interquartile range and the whiskers of the 25th or 75th percentile, respectively. The horizontal lines out of the boxes represent the outliers.

FIGURE 3

Turnaround time result analysis in blood culture reporting. (A) Hourly frequency distributions of blood culture result reporting times. (B) Frequency distributions of specimen collection times and blood culture result reporting times.

FIGURE 4

Antimicrobial susceptibility test reporting under four different workflows. (A) Median turnaround time of antimicrobial susceptibility test in different workflow styles. (B) Median turnaround time of antimicrobial susceptibility test for clinically significant isolates in the four groups.