Meta-analysis: methods for diagnosing intravascular device-related bloodstream infection

Abstract

Background: No consensus exists on the best methods for diagnosis of intravascular device (IVD)-related bloodstream infection.

Purpose: To identify the most accurate methods for diagnosis of IVD-related bloodstream infection.

Data sources: 51 English-language studies published from 1966 to 31 July 2004.

Study selection: Studies of diagnostic tests for IVD-related bloodstream infection that described a reference standard and provided sufficient data to calculate sensitivity and specificity.

Data extraction: Study quality, diagnostic tests examined, patient characteristics, prevalence, sensitivity, and specificity.

Data synthesis: Pooled sensitivity and specificity were calculated for 8 diagnostic methods. Summary measures of accuracy were Q* (the upper leftmost point on the summary receiver-operating characteristic curve) and mean D (a log odds ratio). Subgroup analyses were used to assess heterogeneity. Overall, the most accurate test was paired quantitative blood culture (Q* = 0.94 [95% CI, 0.88 to 1.0]), followed by IVD-drawn quantitative [corrected] blood culture (Q* = 0.89 [CI, 0.79 to 0.99]) and the acridine orange leukocyte cytospin test (Q* = 0.89 [CI, 0.79 to 0.91]). The most accurate catheter segment culture test was quantitative culture (Q* = 0.87 [CI, 0.81 to 0.93]), followed by semi-quantitative culture (Q* = 0.84 [CI, 0.80 to 0.88]). Significant heterogeneity in pooled sensitivity and specificity was observed across all test categories.

Limitations: The limited number of studies of some of the diagnostic methods precludes precise estimates of accuracy.

Conclusions: Paired quantitative blood culture is the most accurate test for diagnosis of IVD-related bloodstream infection. However, most other methods studied showed acceptable sensitivity and specificity (both >0.75) and negative predictive value (>99%). The positive predictive value of all tests increased greatly with high pretest clinical probability. Catheters should not be cultured routinely but rather only if IVD-related bloodstream infection is suspected clinically.