Level and Quality, Not Just Findings: Appraising the Evidence for a Blood Culture Collection Bundle Using the Johns Hopkins Model
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Doctor of Nursing Practice Program, Aspen University
DNP860: Evidence-Based Practice for Quality Improvement
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Month Day, Year
Level and Quality, Not Just Findings: Appraising the Evidence for a Blood Culture Collection Bundle Using the Johns Hopkins Model
Summarizing what studies found is not appraisal. Appraisal asks how much confidence each finding deserves, based on the study's design and how well it was conducted. This paper appraises five key sources from the search on reducing blood culture contamination using the Johns Hopkins evidence-based practice model's levels of evidence and quality ratings, then considers what the body of evidence supports for each component of the proposed collection bundle.
The Appraisal Framework
The Johns Hopkins model rates research evidence on five levels (Dang et al., 2021). The top level holds experimental work, such as randomized trials, along with systematic reviews built from such trials. The second level covers quasi-experimental studies and systematic reviews of quasi-experimental studies, alone or combined with trials. Level III includes nonexperimental and qualitative studies and systematic reviews that include them. Level IV includes the opinions of respected authorities and nationally recognized expert committees, such as clinical practice guidelines and consensus panels. Level V includes literature reviews, quality improvement projects, program evaluations, financial evaluations, case reports, and expert opinion. Each source also receives a quality grade, with A for high quality, B for good quality with some limitations, and C for low quality or major flaws, judged on sample size, control, consistency, and the clarity of methods and conclusions.
Source 1: Systematic Review and Meta-Analysis of Collection Practices
Snyder et al. (2012) conducted a systematic review and meta-analysis for a laboratory medicine best practices initiative, including 9 studies of venipuncture compared with catheter draws, 5 of phlebotomy teams, and 7 of preparation kits. All studies favored venipuncture and phlebotomy teams, with mean odds ratios of 2.69 and 2.58 for contamination with the comparison practices, while preparation kits showed no clear effect. Level: III, because most included studies were observational. Quality: A, because the review used a transparent, systematic method with explicit rating of study quality and consistent findings. What it supports: separate venipuncture and dedicated, trained collectors. What it does not support: the use of prepackaged kits alone.
Source 2: A Within-Patient Trial of Diverting the First Milliliters
Rupp et al. (2017) conducted a prospective controlled trial in an academic emergency department in which 904 patients each had one culture set collected with a device that diverts the first 1.5 to 2 milliliters of blood and one collected by standard procedure. Contamination was 0.22 percent with the device and 1.78 percent with standard collection, and the detection of true bacteremia was not reduced. Level: II, a controlled but not randomized comparison. Quality: B, strong within-patient design and large sample, but conducted at a single academic site with staff who knew they were being studied, which calls for caution about how well the effect will carry over to routine practice elsewhere. What it supports: adding diversion to the bundle.
Source 3: Interrupted Time Series Quality Improvement Study
Self et al. (2013) reported a quality improvement study in an emergency department that converted blood culture collection from a clean to a fully sterile procedure. Contamination fell from 4.3 percent of 7,389 cultures at baseline to 1.7 percent of 6,590 during the intervention, with segmented regression showing an immediate absolute reduction of 2.9 percentage points, sustained below 3 percent throughout the intervention period. Level: V, as a quality improvement study under the Johns Hopkins hierarchy. Quality: A, because the interrupted time series design and segmented regression provide stronger inference than a simple before-and-after comparison, and the setting closely matches ours. Its level is the lowest, but its fit with our department is the closest, and appraisal must weigh both.
Source 4: Comprehensive Review
Doern et al. (2019) published a comprehensive review of blood culture contamination for clinical microbiology laboratories, covering its scope, common contaminants, consequences, and methods of prevention. Level: V, a literature review with expert guidance. Quality: A, written by recognized experts with extensive referencing. What it supports: the significance of the problem, the definition of contamination, and the plausibility of combining several practices; it is not direct evidence of effectiveness.
Source 5: Economic Decision Analysis
Skoglund et al. (2019) built a decision analysis model estimating the costs and benefits of routine use of a diversion device in an emergency department. The model found the device cost-beneficial, with savings driven mainly by the baseline contamination rate and the duration of antibiotics given to patients with falsely positive cultures. Level: V, a financial evaluation. Quality: B, because the model's results depend on assumptions drawn from the literature and one institution's data. What it supports: a business case for diversion, especially where baseline contamination is high, as it is in our department.
What the Body of Evidence Supports
Taken together, the evidence is strongest for separate venipuncture and dedicated, trained collectors, supported by a high-quality Level III systematic review. It is good for initial specimen diversion, supported by a Level II trial and a Level V economic model. It is good for sterile technique, supported by a high-quality Level V improvement study in a similar setting. It does not support preparation kits alone. Under the Johns Hopkins model's approach to synthesis, this body of evidence is consistent, with good to high quality across several levels, which supports translating the bundle into practice as a pilot with careful measurement rather than as an untested system-wide change (Dang et al., 2021).
Gaps the Appraisal Revealed
The appraisal also exposed what the evidence does not answer. No included study tested all three bundle components together, so their combined effect is inferred rather than demonstrated. Most studies were conducted in academic centers with dedicated research or improvement staff, while our department is a community emergency department with high nurse turnover. And few studies reported how long improvements lasted beyond a year. These gaps shape the project design: components will be introduced in sequence so that the contribution of each can be seen, implementation support will be planned for a setting without dedicated improvement staff, and measurement will continue for at least 12 months.
Conclusion
Appraising by level and quality shows that the proposed bundle rests on uneven evidence: strongest for venipuncture and trained collectors, good for diversion and sterile technique, and absent for kits alone. The appraisal changes the project in one way: preparation kits will not be purchased as a stand-alone intervention. It also confirms that the bundle should be tested as an improvement project with measurement, since the best evidence for some components comes from single sites.
References
Dang, D., Dearholt, S. L., Bissett, K., Ascenzi, J., & Whalen, M. (2021). Johns Hopkins evidence-based practice for nurses and healthcare professionals: Model and guidelines (4th ed.). Sigma Theta Tau International.
Doern, G. V., Carroll, K. C., Diekema, D. J., Garey, K. W., Rupp, M. E., Weinstein, M. P., & Sexton, D. J. (2019). Practical guidance for clinical microbiology laboratories: A comprehensive update on the problem of blood culture contamination and a discussion of methods for addressing the problem. Clinical Microbiology Reviews, 33(1), Article e00009-19. https://doi.org/10.1128/CMR.00009-19
Rupp, M. E., Cavalieri, R. J., Marolf, C., & Lyden, E. (2017). Reduction in blood culture contamination through use of initial specimen diversion device. Clinical Infectious Diseases, 65(2), 201-205. https://doi.org/10.1093/cid/cix304
Self, W. H., Speroff, T., Grijalva, C. G., McNaughton, C. D., Ashburn, J., Liu, D., Arbogast, P. G., Russ, S., Storrow, A. B., & Talbot, T. R. (2013). Reducing blood culture contamination in the emergency department: An interrupted time series quality improvement study. Academic Emergency Medicine, 20(1), 89-97. https://doi.org/10.1111/acem.12057
Skoglund, E., Dempsey, C. J., Chen, H., & Garey, K. W. (2019). Estimated clinical and economic impact through use of a novel blood collection device to reduce blood culture contamination in the emergency department: A cost-benefit analysis. Journal of Clinical Microbiology, 57(1), Article e01015-18. https://doi.org/10.1128/JCM.01015-18
Snyder, S. R., Favoretto, A. M., Baetz, R. A., Derzon, J. H., Madison, B. M., Mass, D., Shaw, C. S., Layfield, C. D., Christenson, R. H., & Liebow, E. B. (2012). Effectiveness of practices to reduce blood culture contamination: A Laboratory Medicine Best Practices systematic review and meta-analysis. Clinical Biochemistry, 45(13-14), 999-1011. https://doi.org/10.1016/j.clinbiochem.2012.06.007
How this DNP 860 Module 3 example is structured
DNP860 Module 3 work often appraises studies by level and quality, not by summary. Aspen does not publish module deliverables, so check your classroom for the exact prompt. This example states the hierarchy, rates each source on level and quality with reasons, says what each supports and does not, synthesizes the strength of evidence by bundle component and shows how the appraisal changes the project.
DNP860 Module 3 questions, answered
What does DNP860 Module 3 usually ask for?
The module often asks you to appraise the studies from your search by level of evidence and quality using a named hierarchy, rather than summarizing their findings. Aspen does not publish module deliverables, so your classroom's instructions govern.
What are the Johns Hopkins levels of evidence?
Level I, experimental studies and systematic reviews of them; Level II, quasi-experimental studies; Level III, nonexperimental and qualitative studies; Level IV, expert committee opinion and guidelines; Level V, literature reviews, quality improvement, program and financial evaluations and expert opinion. Each is rated A, B or C for quality.
Can a lower-level study still be important?
Yes. A well-designed quality improvement study in a setting like yours may be more applicable than a higher-level study elsewhere. Appraisal weighs strength, quality and fit together.
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