Laboratory blood tests are ubiquitous among hospitalised patients; ICU patients are subject to a higher number of tests. Recently, some authors have suggested that laboratory blood tests are overused.1 Multiple strategies have been adopted in order to reduce laboratory tests and to ensure appropriate testing; despite this, the economic effects of interventions promoting an evidence-based use of laboratory tests are not yet fully understood. Differences have been noted among physicians as to the amount of resources they use in managing critically ill patients admitted to ICU. However, a larger use of resources has not been associated with reduced length of stay or mortality rate.2 Excessive costs, potential risks and no proof of benefit mandate a re-evaluation of the current approach to routine laboratory test ordering in ICU. Therefore, we performed a clinical audit for promoting a rational, evidence-based use of laboratory tests in an ICU in order to improve the decision-making process of test ordering, decrease unnecessary laboratory tests and reduce sanitary costs.
Ethics approval for the scientific analysis and publication of data (document no. 58) was provided by the Ethical Committee of Parma (Comitato Etico Unico per la Provincia di Parma; Chairperson Prof. F. Gardini) on 5 January 2009, and the study was conducted in the surgical and medical ICU of the tertiary referral teaching hospital of Parma.
Phase 1 (clinical audit): pertinent literature was identified through a computerised search of the MEDLINE database, on which basis, in October 2007 new guidelines for laboratory biochemical test ordering were edited. The working group was composed by two anaesthetists, one biochemist, six surgeons and one economist. Laboratory biochemical tests were classified as ‘routine’ and ‘non-routine’. The choice of determining a single test as routine or non-routine was made according to pertinent literature3 and consensus of the working group. Routine tests included those recommended on admission to ICU; other laboratory tests not included in guidelines were considered routine on the basis of consensus of the working group. Laboratory tests identified as routine were considered as appropriate in any situation whereas clinicians were asked to reduce the number of non-routine tests by ordering tests more relevant to the clinical question. New guidelines included the following main points:
- a specific panel of tests for patients admitted to ICU was produced;
- the practice of bundling multiple laboratory tests together was discouraged;
- the concept that non-routine tests should be ordered only on suspicion of disease, rather than as a search for abnormal values to be corrected was emphasised;
- once a year, the ICU had to examine its own practice in regard to laboratory tests in order to point out excessive or inappropriate test ordering that might be target for actions.
Phase 2 (amelioration action): new guidelines were introduced and implemented in clinical practice, starting from November 2007.
Phase 3 (feedback): prospective data collection was performed during the months of January 2008 (first feedback) and September 2008 (second feedback). A control group was represented by the number of biochemical tests ordered during the month of September 2007, before the introduction of the new guidelines.
The number and costs of laboratory biochemical tests requested during the months of September 2007, January 2008 and September 2008 are shown in Table 1. A significant reduction (P < 0.001) in per-patient number and costs of non-routine tests was noted in January 2008 and September 2008 (Table 2). The characteristics of the ICU patients are shown in Table 3. No differences in terms of length of stay and severity of illness between the examined periods were found. Mortality rate did not significantly differ among the three periods after adjusting for Simplified Acute Physiology Score (SAPS) II.
According to these results, the introduction and implementation of new guidelines into clinical practice led to a relevant reduction in costs for non-routine tests. Various studies report that a reduction in test ordering occurs soon after an amelioration action. However, achieving a durable reduction in test ordering has proved to be problematic, with test ordering often coming back to pre-intervention levels after a short period.4 In our study, a sharp decline in test ordering occurred within 3 months after the implementation of the guidelines and was still present 10 months after the guidelines introduction. This suggests that behavioural attitude in laboratory test ordering might have been structurally modified as a result of the intervention. Our intervention, performed in order to reduce unnecessary laboratory tests, was developed as part of a routine quality assurance process. Although it required participation of physicians and nurses and the support of administrators, our amelioration action imposed no additional costs to the hospital because all data were taken from the hospital database.
The present study has some limitations. For instance, only biochemical laboratory tests were analysed, whereas blood cell counts, blood gas analyses and coagulation tests were not evaluated. Moreover, although we did not find adverse effects due to the reduction in the number of tests, we cannot exclude that some physiologic abnormalities were not detected.
In conclusion, we found an excessive use of laboratory biochemical tests is unnecessary, and that they do not have an impact on patients’ length of stay and mortality in an ICU. On the contrary, ordering laboratory tests according to specific clinical questions may produce a relevant reduction in costs, particularly in high-cost scenarios such as ICUs.
Assistance with the letter: none declared.
Financial support and sponsorship: none declared.
Conflicts of interest: none declared.
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2. Garland A, Shaman Z, Baron J, Connors AF Jr. Physician-attributable differences in intensive care unit costs: a single-center study. Am J Respir Crit Care Med
3. Ezzie ME, Aberegg SK, O’Brien JM Jr. Laboratory testing in the intensive care unit. Crit Care Clin
4. Isouard G. A quality management intervention to improve clinical laboratory use in acute myocardial infarction. Med J Aust