Decreased Mortality Associated With Prompt Gram Staining of Blood Cultures

Joan Barenfanger, MD; Donald R. Graham, MD; Lavanya Kolluri, MD: Gaurav Sangwan, MD; Jerry Lawhorn; Cheryl A. Drake; Steven J. Verhulst, PhD; Ryan Peterson; Lauren B. Moja, PharmD; Matthew M. Ertmoed, PharmD; Ashley B. Moja; Douglas W. Shevlin, MD; Robert Vautrain, MD; Charles D. Callahan, PhD


Am J Clin Pathol. 2008;130(6):870-876. 

In This Article

Abstract and Introduction


Gram stains of positive blood cultures are the most important factor influencing appropriate therapy. The sooner appropriate therapy is initiated, the better. Therefore, it is reasonable to expect that the sooner Gram stains are performed, the better. To determine the value of timely Gram stains and whether improvement in Gram stain turnaround time (TAT) is feasible, we compared data for matched pairs of patients with cultures processed promptly (<1 hour TAT) with data for patients with cultures not processed promptly (1 hour TAT) and then monitored TAT by control charting.

In 99 matched pairs, average difference in time to detection of positive blood cultures within a pair of patients was less than 0.1 hour. For the less than 1 hour TAT group, the average TAT and crude mortality were 0.1 hour and 10.1%, respectively; for the 1 hour or longer TAT group, they were 3.3 hours and 19.2%, respectively (P < .0001 and P = .0389, respectively). After multifaceted efforts, we achieved significant improvement in the TAT for Gram stains.


The Institute of Medicine has recommended that medical practices become more patient-centered.[1] Two notable accomplishments are in the care of myocardial infarction and stroke. In patients with acute myocardial infarction, reduced door-to-balloon time for primary angioplasty decreases mortality.[2] Likewise, in the setting of stroke, studies suggest that the maximum benefit of thrombolytic therapy occurs in the first 3 hours after onset of symptoms.[3] In each disease, acceleration of the provision of appropriate care results in improved outcomes, ie, patients who receive appropriate therapy faster have decreased morbidity and mortality.

Pathologists and clinical microbiologists may have a similar opportunity to improve patient outcomes by more timely processing of Gram stains for positive blood cultures. However, it is possible that delayed processing of positive cultures may have little impact on the care of patients because up to 75% of patients who had blood drawn for culturing have already begun to receive presumptive antibiotics before their specimens yielded an organism.[4] Nevertheless, there is ample evidence that delays in initiation of appropriate therapy have adverse consequences.[5,6,7,8] In addition, Beckmann et al[9] found that increased time to notification of positive blood culture results was associated with increased length of stay in the hospital. Other benefits of early notification (such as the use of more narrow-spectrum antibiotics and improved antibiotic stewardship) would also be expected.[10]

This study evaluated the timely processing of positive cultures (ie, rapid Gram staining and notification of caregivers) compared with delayed processing by using matched control subjects. We then evaluated whether efforts to accomplish effective 24-hour, 7-day-per-week coverage of this duty were achievable in a hospital laboratory.


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