Drawing a Line Between Midlines and Central Lines

Reviewed by Lauren M. DiBiase, MS; University of North Carolina Hospitals

Hogle et al. conducted a retrospective surveillance study at five acute care hospitals over a 12- month timeframe that compared the incidence of CLABSI vs. midline associated BSIs (MLABSI).  Infection Preventionists identified CLABSI and MLABSI cases as part of routine HAI surveillance. CLABSI were defined using NHSN standard definitions and MLABSI was defined as primary BSI that occurred in a patient with a midline that had been in place for more than two calendar days prior to the date of the laboratory-confirmed BSI. Primary BSIs identified in patients who had both a midline and a central line were counted as CLABSIs.

During the 12-month study period, there were 165,166 central line-days and 26,063 midline-days among all five hospitals. Overall catheter utilization was 0.21 for central lines and 0.034 for midlines. Among the hospitals, 23 MLABSIs were identified during the study period for an overall MLABSI incidence of 0.88 per 1,000 midline-days.  During the same period, 178 CLABSIs were identified, resulting in a CLABSI incidence of 1.10 per 1,000 central line-days. The difference between the incidence of MLABSIs and that of CLABSIs was not statistically significant (p = 0.37).  As more hospital systems seek out alternatives to central lines, including increasing their use of midlines, hospitals should be aware that MLABSI incidence is not negligible and midlines do not eliminate risk of catheter-associated BSIs.  Hospitals using midline catheters should consider including MLABSI surveillance as part of their overall vascular access safety program.


Hogle NJ, Balzer KM, Ross BG, Wuerz L, Greendyke WG, Furuya EY, Simon MS, Calfee DP. A comparison of the incidence of midline catheter-associated bloodstream infections to that of central line-associated bloodstream infections in 5 acute care hospitals. Am J Infect Control. 2019 Dec 5. pii: S0196-6553(19)30959-9. https://doi.org/10.1016/j.ajic.2019.11.004 

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