Developing criteria for ordering common ancillary services

Choosing which in-hospital laboratory tests to target for intervention: a scoping review

INTRODUCTION

Some laboratory testing practices may be of low value, leading to wasted resources and potential patient harm. Our scoping review investigated factors and processes that developers report using to inform decisions about what tests to target for practice improvement.

METHODS

We searched Medline on May 30th, 2019 and June 28th, 2021 and included guidelines, recommendation statements, or empirical studies related to test ordering practices. Studies were included if they were conducted in a tertiary care setting, reported making a choice about a specific test requiring intervention, and reported at least one factor informing that choice. We extracted descriptive details, tests chosen, processes used to make the choice, and factors guiding test choice.

RESULTS

From 114 eligible studies, we identified 30 factors related to test choice including clinical value, cost, prevalence of test, quality of test, and actionability of test results. We identified nine different processes used to inform decisions regarding where to spend intervention resources.

CONCLUSIONS

Intervention developers face difficult choices when deciding where to put scarce resources intended to improve test utilization. Factors and processes identified here can be used to inform a framework to help intervention developers make choices relevant to improving testing practices.

Effects of implementing a protocol for arterial blood gas use on ordering practices and diagnostic yield

BACKGROUND

The arterial blood gas (ABG) is a valuable and commonly used laboratory test. This prospective cohort study examined the variability of ABG ordering through the implementation of an evidence-based protocol.

METHODS

The study consisted of two 6-week periods. The protocol consisted of evidence-based and consensus opinion based indications for ABGs. In the first phase (initial 6 weeks), respiratory therapists recorded the indications for ABGs ordered by clinicians. In the second phase, all medical and surgical physicians were trained on the clinical rationale behind the protocol and were instructed to write the indication for each ABG with the order. Rates of ABGs/patient/day were measured in aggregate and per indication. Multivariate regression was used for adjusted comparisons between indications within the protocol.

RESULTS

After protocol implementation, there was a significant decrease in ABGs from 2158 to 1674 (p=0.001), and after adjusting for daily census, there was a significant decrease from 35.3 ABGs/100 patients/day to 26.5 ABGs/100 patients/day (p<0.001), with no change in mortality or demographic characteristics between the populations. The percent of ABGs with normal range values for pH, PaCO2, and PaO2 decreased from 13.3% to 9.6% after implementation (p<0.001). Multivariate analysis revealed a 14% decrease in daily ABGs (p=0.001), a 15% decrease in weaning trial ABGs (p=0.039), and a 15% increase in ABGs ordered following a change in minute ventilation (p=0.004). Cost minimization analysis estimated annual institutional savings to be $87,565.

CONCLUSIONS

Implementation of an evidence based protocol for ABG use resulted in fewer ABGs/patient/day largely from reduction of routine, daily ABGs. Ordering patterns for ABGs appeared to shift towards more clinically appropriate/relevant indications.

LEVEL OF EVIDENCE

2b.

What proportion of common diagnostic tests appear redundant?

PURPOSE

To identify ancillary tests for which there are criteria defining the earliest interval at which a repeat test might be indicated, to determine how often each test is repeated earlier than these intervals and, if repeated, provides useful information.

SUBJECTS AND METHODS

We performed a retrospective cohort study of 6,007 adults discharged from a large teaching hospital during a 3-month period in 1991. We measured the proportion of commonly performed diagnostic tests that were redundant, and their associated charges.

RESULTS

Of the 6,007 patients discharged, 5,289 (88%) had at least one of 12 target tests performed. Overall, 78,798 of the target tests were performed during the study period, of which 22,237 (28%) were repeated earlier than test-specific predefined intervals. This percentage varied substantially by test (range, 2% to 62%). To assess how many early repeats were justified, we performed chart reviews in a random sample stratified by test. For two tests, nearly all the initial results in the sample were abnormal, and all repeats were considered justified. Of early repeats following a normal initial result for the remaining 10 tests, chart review found no clinical indication for 92%, and a weighted mean of 40% appeared redundant. Overall, 8.6% of these 10 tests appeared redundant; if these were not performed, the annual charge reductions would be $930,000 at our hospital, although the impact on costs would be much smaller.

CONCLUSIONS

For some tests, an important proportion are repeated too early to provide useful clinical information. Most such tests might be eliminated using computerized reminder systems.

Practice guideline for arterial blood gas measurement in the intensive care unit decreases numbers and increases appropriateness of tests

OBJECTIVE

To test the hypothesis that implementation of a practice guideline for blood gas measurement would decrease numbers and increase appropriateness of tests (according to criteria in the guideline) for up to 1 yr after introduction of the guideline.

DESIGN

Numbers of tests and appropriateness of each test were measured retrospectively during each of five periods: two baseline periods 2 yrs and 1 yr before introduction of the guideline and three follow-up periods 2 to 3 months, 6 to 7 months, and 12 to 13 months after introduction of the guideline.

SETTING

A ten-bed multidisciplinary intensive care unit (ICU) within a 500-bed tertiary teaching hospital.

PATIENTS

A random sample of 30 patients admitted to the ICU during each of the periods specified above.

INTERVENTIONS

The nominal group process was used to develop a new guideline and a multipronged educational approach was used to facilitate implementation of the guideline.

MEASUREMENTS AND MAIN RESULTS

At 2 to 3 months, test numbers decreased from 4.9 +/- 1.6 to 3.1 +/- 1.8 (SD) tests/patient/day and to 2.4 +/- 1.2 tests/patient/day at 12 to 13 months. Appropriateness increased from a mean of 44% at baseline to 78% at 2 to 3 months and 79% at 12 to 13 months. There were no differences in Acute Physiology and Chronic Health Evaluation scores or ICU mortality among the patient groups and no differences in number of ventilator days or time to wean from ventilation. Cost-minimization analysis showed that the incremental cost-saving 1 yr after introduction of the guideline was $19.18 per patient per day.

CONCLUSIONS

Implementation of this guideline for arterial blood gas measurement increases efficiency of test utilization without prolonging mechanical ventilation or affecting outcome.