Alerting physicians during electronic order entry effectively reduces unnecessary repeat PCR testing for Clostridium difficile. J Clin Microbiol. 2013;51:3872-3874. [PMID: 23985918 DOI: 10.1128/jcm.01724-13]

Impact of customized electronic duplicate order alerts on microbiology test ordering: Financial and environmental cost savings

OBJECTIVE

To estimate cost savings after implementation of customized electronic duplicate order alerts.

DESIGN

Alerts were implemented for microbiology tests at the largest public hospital in Victoria, Australia. These alerts were designed to pop up at the point of test ordering to inform the clinician that the test had previously been ordered and to suggest appropriate reordering time frames and indications.

RESULTS

In a 6-month audit of urine culture (our most commonly ordered test) after alert implementation, 2,904 duplicate requesters proceeded with the request and 2,549 tests were cancelled, for a 47% reduction in test ordering. For fecal polymerase chain reaction (PCR), our second most common test, there was a 54% reduction in test ordering. For our most commonly ordered expensive test, hepatitis C PCR, there was a 42% reduction in test ordering: 25 tests were cancelled.Cancelled tests resulted in estimated savings of AU$52,382 (US$33,960) for urine culture, AU$34,914 (US$22,442) for fecal PCR, AU$4,506 (US$2,896) for hepatitis C PCR. For cancelled hepatitis B PCR and Epstein-Barr virus (EBV) and cytomegalovirus (CMV) serology, the cost savings was AU$8,472 (US$5445). The estimated financial cost saving in direct hospital costs for these 6 assays was AU$100,274 (US$67,925) over the 6-month period. Environmental waste cost saving by weight was estimated to be 280 kg. Greenhouse gas footprint, measured in carbon dioxide equivalent emissions for cancelled EBV and CMV serology tests, resulted in a saving of at least 17,711 g, equivalent to driving 115 km in a standard car.

CONCLUSION

Customized alerts issued at the time of test ordering can have enormous impacts on reducing cost, waste, and unnecessary testing.

Working with the Electronic Health Record and Laboratory Information System to Maximize Ordering and Reporting of Molecular Microbiology Results

Molecular microbiology assays have a higher cost of testing compared to traditional methods and need to be utilized appropriately. Results from these assays may also require interpretation and appropriate follow-up. Electronic tools available in the electronic health record and laboratory information system can be deployed both preanalytically and postanalytically to influence ordering behaviors and positively impact diagnostic stewardship. Next generation technologies, such as machine learning and artificial intelligence, have the potential to expand upon the capabilities currently available and warrant additional study and development but also require regulation around their use in health care.

Clostridioides difficile dynamic electronic order panel, an effective automated intervention to reduce inappropriate inpatient ordering

BACKGROUND

Ordering Clostridioides difficile diagnostics without appropriate clinical indications can result in inappropriate antibiotic prescribing and misdiagnosis of hospital onset C. difficile infection. Manual processes such as provider review of order appropriateness may detract from other infection control or antibiotic stewardship activities.

METHODS

We developed an evidence-based clinical algorithm that defined appropriateness criteria for testing for C. difficile infection. We then implemented an electronic medical record-based order-entry tool that utilized discrete branches within the clinical algorithm including history of prior C. difficile test results, laxative or stool-softener administration, and documentation of unformed bowel movements. Testing guidance was then dynamically displayed with supporting patient data. We compared the rate of completed C. difficile tests after implementation of this intervention at 5 hospitals to a historic baseline in which a best-practice advisory was used.

RESULTS

Using mixed-effects Poisson regression, we found that the intervention was associated with a reduction in the incidence rate of both C. difficile ordering (incidence rate ratio [IRR], 0.74; 95% confidence interval [CI], 0.63-0.88; P = .001) and C. difficile-positive tests (IRR, 0.83; 95% CI, 0.76-0.91; P < .001). On segmented regression analysis, we identified a sustained reduction in orders over time among academic hospitals and a new reduction in orders over time among community hospitals.

CONCLUSIONS

An evidence-based dynamic order panel, integrated within the electronic medical record, was associated with a reduction in both C. difficile ordering and positive tests in comparison to a best practice advisory, although the impact varied between academic and community facilities.

Clinical Outcomes of Treated and Untreated C. difficile PCR-Positive/Toxin-Negative Adult Hospitalized Patients: a Quasi-Experimental Noninferiority Study

Clostridioides difficile infection (CDI) is routinely diagnosed by PCR, with or without toxin enzyme immunoassay testing. The role of therapy for positive PCR and negative toxin remains unclear. The objective of this study was to determine whether clinical outcomes of PCR+/cycle threshold-based toxin (CT-toxin)- individuals vary by result reporting and treatment strategy. We performed a quasiexperimental noninferiority study comparing clinical outcomes of PCR+/CT-toxin- individuals by reporting PCR result only (most patients treated) with reporting CT-toxin result only (most patients untreated) in a single-center, tertiary academic hospital. The primary outcome was symptomatic PCR+/CT-toxin+ conversion at 8 weeks. Secondary outcomes included 7-day diarrhea resolution, hospital length of stay, and 30-day all-cause mortality. A total of 663 PCR+/CT-toxin- test results were analyzed from 632 individuals with a median age of 61 years (interquartile range [IQR], 44 to 72) and 50.4% immunocompromised. Individuals in the preintervention group were more likely to have received CDI therapy than those in the intervention group (91.5 versus 15.1%; P < 0.001). Symptomatic toxin conversion at 8 weeks and hospital length of stay failed to establish the predefined thresholds for noninferiority. Lack of diarrhea resolution at 7 days and 30-day all-cause mortality was similar and established noninferiority (20.0 versus 13.7%; adjusted odds ratio [aOR], 0.57; 90% confidence interval [CI], 0.32 to 1.01; P = 0.1; and 8.6 versus 6.5%; aOR, 0.46; 90% CI, 0.20 to 1.04; P = 0.12). These data support the safety of withholding antibiotics for selected hospitalized individuals with suspected CDI but negative toxin.

Diagnostic Stewardship as a Team Sport: Interdisciplinary Perspectives on Improved Implementation of Interventions and Effect Measurement

Diagnostic stewardship aims to deliver the right test to the right patient at the right time and is optimally combined with antimicrobial stewardship to allow for the right interpretation to translate into the right antimicrobial at the right time. Laboratorians, physicians, pharmacists, and other healthcare providers have an opportunity to improve the effectiveness of diagnostics through collaborative activities around pre-analytical and post-analytical periods of diagnostic testing. Additionally, special considerations should be given to measuring the effectiveness of diagnostics over time. Herein, we perform a narrative review of the literature on these potential optimization opportunities and the temporal factors that can yield changes in diagnostic effectiveness. Our objective is to inform on these considerations to ensure enhanced value through improved implementation and measurement of effectiveness for local stakeholder metrics and/or clinical outcomes research.

The Impact of Clinical Decision Support Alerts on Clostridioides difficile Testing: A Systematic Review

BACKGROUND

Several studies have investigated the utility of electronic decision support alerts in diagnostic stewardship for Clostridioides difficile infection (CDI). However, it is unclear if alerts are effective in reducing inappropriate CDI testing and/or CDI rates. The aim of this systematic review was to determine if alerts related to CDI diagnostic stewardship are effective at reducing inappropriate CDI testing volume and CDI rates among hospitalized adult patients.

METHODS

We searched Ovid Medline and 5 other databases for original studies evaluating the association between alerts for CDI diagnosis and CDI testing volume and/or CDI rate. Two investigators independently extracted data on study characteristics, study design, alert triggers, cointerventions, and study outcomes.

RESULTS

Eleven studies met criteria for inclusion. Studies varied significantly in alert triggers and in study outcomes. Six of 11 studies demonstrated a statistically significant decrease in CDI testing volume, 6 of 6 studies evaluating appropriateness of CDI testing found a significant reduction in the proportion of inappropriate testing, and 4 of 7 studies measuring CDI rate demonstrated a significant decrease in the CDI rate in the postintervention vs preintervention period. The magnitude of the increase in appropriate CDI testing varied, with some studies reporting an increase with minimal clinical significance.

CONCLUSIONS

The use of electronic alerts for diagnostic stewardship for C. difficile was associated with reductions in CDI testing, the proportion of inappropriate CDI testing, and rates of CDI in most studies. However, broader concerns related to alerts remain understudied, including unintended adverse consequences and alert fatigue.

Advances and required improvements in methods to diagnosing Clostridioides difficile infections in the healthcare setting

INTRODUCTION

Clostrididioides difficile is associated with adverse clinical outcomes and increased morbidity, mortality, length of hospital stay, and health-care costs.Areas Covered: We searched relevant papers in PubMed for the last 10 years. In major papers, we scanned the bibliographies to ensure that important articles were included. This review addresses the evolving epidemiology of Clostridioides difficile infection (CDI) and discusses novel methods/approaches for improving the diagnosis of this important disease.

EXPERT OPINION

No single diagnostic test to date has demonstrated optimum sensitivity and specificity for detection of CDI. Many institutions have developed multi-step algorithms consistent with guidelines established by various professional societies. Some institutions have successfully tried to improve the pretest probability of molecular assays by implementing appropriate sample rejection criteria and establishing best practice alerts at the time of electronic order entry. Others have established PCR cycle threshold cutoffs to attempt to differentiate symptomatic patients from asymptomatic carriers or to make predictions about severity of disease with variable success. As research advances our understanding of C. difficile pathogenesis and pathophysiology, more information on CDI specific biomarkers is emerging. Finally, assessments of the microbiome and metabolome may expand the diagnostic armamentarium with advances in mass spectrometry and sequencing technologies.

Burden and risk factors for inappropriate Clostridioides Difficile infection testing among hospitalized patients

BACKGROUND

The purpose of this study was to identify the burden and risk factors for inappropriate Clostridioides difficile infection (CDI) testing.

METHODS

This was a retrospective cohort study among adults hospitalized between 2010 and 2019. Inappropriate CDI testing was defined as a formed stool specimen, an order within 7 days of a previously negative test, or an order within 24 hours of laxative administration.

RESULTS

A total of 51,302 CDI orders were placed for 29,840 unique patients. 59% were appropriate and 41% were inappropriate. An additional 24% of the appropriate orders never resulted. Risk factors for inappropriate testing included orders placed by a nurse practitioner, orders placed by high-ordering providers, specific hospital units, fever, and leukocytosis.

CONCLUSIONS

Nearly half of all CDI orders were inappropriate among hospitalized patients, and an additional 24% of test results never returned. Provider- and patient-level risk factors included type of provider, specific hospital units, and signs of sepsis.

Impact of a Clostridioides Difficile Testing Computerized Clinical Decision Support Tool on an Adult Stem Cell Transplantation and Hematologic Malignancies Unit

Clostridioides difficile infection rates are higher in hospitalized hematopoietic stem cell transplantation (HSCT) recipients and patients with hematologic malignancy (HM) compared with the general population. This is related both to extensive exposure to antibiotics as well as to frequent and often prolonged hospitalization. In this population, with numerous potential causes of diarrhea, a subset of C difficile detected is presumed to represent colonization rather than clinical infection. The use of decision support tools to guide ordering in hospitalized patients has been reported to decrease both C difficile testing and detection rates. Following implementation of a computerized decision support tool on our HSCT/HM unit, we observed a >2-fold decrease in C difficile testing volume and National Healthcare Safety Network-defined laboratory identifications of C difficile. Furthermore, the rate of oral vancomycin use, as well as the incidence of vancomycin-resistant enterococci colonization and bloodstream infection, decreased in the postintervention period.

Prescriber Behavior in Clostridioides difficile Testing: A 3-Hospital Diagnostic Stewardship Intervention

Computerized clinical decision support (CCDS) significantly reduced Clostridioides difficile testing at 3 hospitals; from 12.6 to 9.5, from 10.1 to 6.4, and from 14.0 to 9.6 average weekly tests per 1000 inpatient days. There were no related adverse events. Senior providers were more likely than interns or residents to follow CCDS.

Minimum retesting intervals in practice: 10 years experience

Background

Minimum retesting intervals (MRI) are a popular demand management solution for the identification and reduction of over-utilized tests. In 2011 Association of Clinical Biochemistry and Laboratory Medicines (ACB) published evidence-based recommendations for the use of MRI.

Aim

The aim of the paper was to review the use of MRI over the period since the introduction of these recommendations in 2011 to 2020 and compare it to previous published data between 2000-2010.

Methods

A multi-source literature search was performed to identify studies that reported the use of a MRI in the management or identification of inappropriate testing between the years prior to (2000–2010) and after implementation (2011–2020) of these recommendations.

Results

31 studies were identified which met the acceptance criteria (2000–2010 n=4, 2011–2020 n=27). Between 2000 and 2010 4.6% of tests (203,104/4,425,311) were identified as failing a defined MRI which rose to 11.8% of tests (2,691,591/22,777,288) in the 2011–2020 period. For those studies between 2011 and 2020 reporting predicted savings (n=20), 14.3% of tests (1,079,972/750,580) were cancelled, representing a total saving of 2.9 M Euros or 2.77 Euro/test. The most popular rejected test was Haemoglobin A1c which accounted for nearly a quarter of the total number of rejected tests. 13 out 27 studies used the ACB recommendations.

Conclusions

MRI are now an established, safe and sustainable demand management tool for the identification and management of inappropriate testing. Evidence based consensus recommendations have supported the adoption of this demand management tool into practice across multiple healthcare settings globally and harmonizing laboratory practice.

Impact of an electronic hard-stop clinical decision support tool to limit repeat Clostridioides difficile toxin enzyme immunoassay testing on test utilization

We performed an intervention evaluating the impact of an electronic hard-stop clinical decision support tool on repeat Clostridioides difficile (CD) toxin enzyme immunoassay (T-EIA) testing. The CD testing rate and number of admissions with repeat tests decreased significantly postintervention (P < .01 for both); the percentage of positive tests was unchanged (P = .27).

Multicenter Clinical Validation of the Molecular BD Max Enteric Viral Panel for Detection of Enteric Pathogens

The conventional methodology for gastrointestinal pathogen detection remains time-consuming, expensive, and of limited sensitivity. The objective of this study was to evaluate the performance of the BD Max enteric viral panel (Max EVP) assay for identification of viral pathogens in stool specimens from individuals with symptoms of acute gastroenteritis, enteritis, or colitis. Prospective and archival stool specimens from adult and pediatric patients with diarrhea were collected in Cary-Blair medium or unpreserved containers. The results for specimens tested by the Max EVP (on the BD Max platform) were compared to those obtained by the reference method (alternate PCR assays, followed by bidirectional sequencing). Positive percent agreement (PPA) and negative percent agreement (NPA) were calculated. A total of 2,239 specimens were collected, with 2,148 being included for analysis. In this population, 39.6% of specimens were from outpatients, 42.1% were from patients <21 years old, and 49.7% were from females. Prevalence rates for prospective specimens were 7.3%, 4.5%, 3.5%, 2.4%, and 1.2% for norovirus, sapovirus, astrovirus, rotavirus, and adenovirus, respectively. PPA was 92.8%, 84.9%, 93.0%, 100%, and 95.6%, for norovirus, sapovirus, astrovirus, rotavirus, and adenovirus, respectively. NPA was ≥99.4% for all targets. In conjunction with the clinical presentation, laboratory findings, and epidemiological information, the Max EVP assay is effective for the differential diagnosis of enteric disease caused by norovirus, sapovirus, astrovirus, rotavirus, and adenovirus. This assay can be used individually for patients at high risk for a viral enteropathogen (e.g., in outbreak settings) or as an adjunct to other enteric bacterial panels.

Outcome of Electronic Order Alert Intervention Relative to Toxigenic Clostridium difficile PCR Analysis and Hospital-Onset C difficile Infection in a Multihospital Health Care System

OBJECTIVES

Concern exists regarding overdiagnosis of Clostridium difficile infection (CDI) via molecular modalities. We determined effects of a preanalytic order intervention on laboratory and CDI prevention measures in a multihospital system.

METHODS

Intervals before and following implementation of a CDI electronic order alert (relative to appropriate testing scenario) were assessed for C difficile test volume and positivity rate, hospital-onset CDI frequency, and hospital-onset C difficile standardized infection ratio (SIR). C difficile detection occurred by PCR throughout the study.

RESULTS

During the first half of 2015, testing volume was 1,578, with 88 hospital-onset CDIs. Following implementation, 18.9% and 56.8% reductions in volume and hospital-onset CDIs were realized, respectively, in the first half of 2017. Regression analysis revealed decreasing trends in PCR volume, positivity rate, hospital-onset CDI frequency, and SIR in larger facilities.

CONCLUSIONS

Preanalytic considerations affect not only the microbiology laboratory but also hospital infection prevention in the context of CDI.

Hardwiring diagnostic stewardship using electronic ordering restrictions for gastrointestinal pathogen testing

OBJECTIVE

To evaluate the impact of a hard stop in the electronic health record (EHR) on inappropriate gastrointestinal pathogen panel testing (GIPP).

DESIGN

We used a quasi-experimental study to evaluate testing before and after the implementation of an EHR alert to stop inappropriate GIPP ordering.

SETTING

Midwest academic medical center.

PARTICIPANTS

Hospitalized patients with diarrhea for which GIPP testing was ordered, between January 2016 through March 2017 (period 1) and April 2017 through June 2018 (period 2).

INTERVENTION

A hard stop in the EHR prevented clinicians from ordering a GIPP more than once per admission or in patients hospitalized for &gt;72 hours.

RESULTS

During period 1, 1,587 GIPP tests were ordered over 212,212 patient days, at a rate of 7.48 per 1,000 patient days. In period 2, 1,165 GIPP tests were ordered over 222,343 patient days, at a rate of 5.24 per 1,000 patient days. The Poisson model estimated a 30% reduction in total GIPP ordering rates between the 2 periods (relative risk, 0.70; 95% confidence interval [CI], 0.63-0.78; P 72 hours.

Relevance or performance: potential savings associated with verification of prior results before performing microbiology analysis

OBJECTIVE

In an era of rising healthcare expenditures, it is critical to find ways to decrease cost. The objective of this study is to evaluate the number of repeated tests and the associated cost savings in a university-affiliated hospital.

METHODS

The following 7 microbiology analysis were assessed for nonrepeat testing: HCV antibody, HBV core antibody, CMV IgG, rubella IgG, Treponema pallidum antibodies, Clostridioides difficile toxin detection, and vancomycin-resistant enterococci PCR. Presence of a prior positive result leads to the cancellation of subsequent orders.

RESULTS

Percentages of not repeated test ranged from 0.1% to 21.4%. Rubella IgG had the highest proportion of unnecessary repeat testing. Total cost savings were estimated at $33,627 for 2016.

CONCLUSION

Unnecessary repeated microbiologic test can account for a non-negligible part of total volume test. Use of an automated software to detect unnecessary repeated microbiologic test through laboratory information system can generate important savings.

Impact of Case-Specific Education and Face-to-Face Feedback to Prescribers and Nurses in the Management of Hospitalized Patients With a Positive Clostridium difficile Test

Background

Approaches to changing providers’ behavior around Clostridium difficile (CD) management are needed. We hypothesized that case-specific teaching points and face-to-face discussions with prescribers and nurses would improve management of patients with a positive CD test.

Methods

Charts of patients age ≥18 years with positive CD tests hospitalized July 2016 to May 2017 were prospectively reviewed to assess CD practices and generate management recommendations. The study had 4 periods: baseline (pre-intervention), intervention #1, observation, and intervention #2. Both interventions consisted of an in-person, real-time, case-based discussion and education by a CD Action Team (CDAT). Assessment occurred within 24 hours of a positive CD test for all periods; during the intervention periods, management was also assessed within 48 hours after CDAT-delivered recommendations. Outcomes included proportion of patients receiving optimized treatment and incidence rate ratios of practice changes (both CDAT-prompted and CDAT-independent).

Results

Overall, the CDAT made recommendations to 84 of 96 CD cases during intervention periods, and providers accepted 43% of CDAT recommendations. The implementation of the CDAT led to significant improvement in bowel movement (BM) documentation, use of proton pump inhibitors, and antibiotic selection for non-CD infections. Selection of CD-specific therapy improved only in the first intervention period. Laxative use and treatment of CD colonization cases remained unchanged. Only BM documentation, a nurse-driven task, was sustained independent of CDAT prompting.

Conclusions

A behavioral approach to changing the management of positive CD tests led to self-sustained practice changes among nurses but not physicians. Better understanding of prescribers’ decision-making is needed to devise enduring interventions.

An Audit of Repeat Testing at an Academic Medical Center: Consistency of Order Patterns With Recommendations and Potential Cost Savings

OBJECTIVES

To evaluate the prevalence of potentially unnecessary repeat testing (PURT) and the associated economic burden for an inpatient population at a large academic medical facility.

METHODS

We evaluated all inpatient test orders during 2016 for PURT by comparing the intertest times to published recommendations. Potential cost savings were estimated using the Centers for Medicare & Medicaid Services maximum allowable reimbursement rate. We evaluated result positivity as a determinant of PURT through logistic regression.

RESULTS

Of the evaluated 4,242 repeated target tests, 1,849 (44%) were identified as PURT, representing an estimated cost-savings opportunity of $37,376. Collectively, the association of result positivity and PURT was statistically significant (relative risk, 1.2; 95% confidence interval, 1.1-1.3; P < .001).

CONCLUSIONS

PURT contributes to unnecessary health care costs. We found that a small percentage of providers account for the majority of PURT, and PURT is positively associated with result positivity.

Predicting Low Information Laboratory Diagnostic Tests

Escalating healthcare costs and inconsistent quality is exacerbated by clinical practice variability. Diagnostic testing is the highest volume medical activity, but human intuition is typically unreliable for quantitative inferences on diagnostic performance characteristics. Electronic medical records from a tertiary academic hospital (2008-2014) allow us to systematically predict laboratory pre-test probabilities of being normal under different conditions. We find that low yield laboratory tests are common (e.g., ~90% of blood cultures are normal). Clinical decision support could triage cases based on available data, such as consecutive use (e.g., lactate, potassium, and troponin are >90% normal given two previously normal results) or more complex patterns assimilated through common machine learning methods (nearly 100% precision for the top 1% of several example labs).

Low Yield of FilmArray GI Panel in Hospitalized Patients with Diarrhea: an Opportunity for Diagnostic Stewardship Intervention

The FilmArray GI panel (BioFire Diagnostics, Salt Lake City, UT) is a multiplex, on-demand, sample-to-answer, real-time PCR assay for the syndromic diagnosis of infectious gastroenteritis that has become widely adopted and, in some instances, has replaced conventional stool culture and parasite exams. Conventional testing has historically been restricted among hospitalized patients due to low diagnostic yield, but it is not known whether use of the FilmArray GI panel should be circumscribed. Cary-Blair stool samples submitted for FilmArray GI panel in adult patients admitted to an academic hospital from August 2015 to January 2017 were included in this study. Of 481 tests performed >72 h after admission, 29 (6.0%) were positive, all for a single target, excluding Clostridium difficile When follow-up tests beyond the first positive per hospitalization were excluded, 20 (4.8%) of 414 tests were positive. There was no difference in yield by immune status. Most targets detected were viral (79% of all positives [n = 23] and 70% in unique patients [n = 14]). All four cases positive for a bacterial target could not be confirmed and presentation was atypical, suggesting possible false positives. After removing potential false positives and chronic viral shedders, the yield was 3.0% (12/406). Repeat testing performed >72 h after admission and following a negative result within the first 72 h was done in 19 patients and 100% (22/22) remained negative. The FilmArray GI panel has low yield in adult patients hospitalized for >72 h, similar to conventional stool microbiology tests, and it is reasonable to restrict its use in this population.

Reducing Inappropriate Testing for the Evaluation of Diarrhea Among Hospitalized Patients

BACKGROUND

Diarrhea is one of the most common illnesses in the United States. Evaluation frequently does not follow established guidelines. The objective of this study was to evaluate the effectiveness of a computerized physician order entry-based test guidance algorithm with regard to the clinical, financial, and operational impacts.

METHODS

Our population was patients with diarrheal illness at a tertiary academic medical center. The intervention was a computerized physician order entry-based test guidance algorithm that restricted the use of stool cultures and ova and parasites testing of diarrhea in the adult inpatient location vs nonintervention sites, which were the emergency department, pediatric inpatient and adult and pediatric outpatient locations. We measured stool culture, ova and parasites, and Clostridium difficile testing rates from July 1, 2012 to January 31, 2016. Additionally, we calculated advisor usage, consults generated, accuracy of information, and cost savings.

RESULTS

There was a significant decrease in stool culture and ova and parasites testing rates at the adult inpatient (P = .001 for both), pediatric (P < .001 for both), and adult emergency department (P < .001; P = .009) locations. The decrease at the intervention site was immediate, whereas the other locations showed a delayed but sustained decrease that suggests a collateral impact. A significant increase in the rate of stool culture and ova and parasites testing was observed in the outpatient setting (P = .02 and P = .001). We estimate that $21,931 was saved annually.

CONCLUSIONS

A point-of-order test restriction algorithm for hospitalized adults with diarrhea reduced stool testing. Similar programs should be considered at other institutions and for the evaluation of other conditions.

Current knowledge on the laboratory diagnosis of Clostridium difficile infection

Clostridium difficile (C. difficile) is a spore-forming, toxin-producing, gram-positive anaerobic bacterium that is the principal etiologic agent of antibiotic-associated diarrhea. Infection with C. difficile (CDI) is characterized by diarrhea in clinical syndromes that vary from self-limited to mild or severe. Since its initial recognition as the causative agent of pseudomembranous colitis, C. difficile has spread around the world. CDI is one of the most common healthcare-associated infections and a significant cause of morbidity and mortality among older adult hospitalized patients. Due to extensive antibiotic usage, the number of CDIs has increased. Diagnosis of CDI is often difficult and has a substantial impact on the management of patients with the disease, mainly with regards to antibiotic management. The diagnosis of CDI is primarily based on the clinical signs and symptoms and is only confirmed by laboratory testing. Despite the high burden of CDI and the increasing interest in the disease, episodes of CDI are often misdiagnosed. The reasons for misdiagnosis are the lack of clinical suspicion or the use of inappropriate tests. The proper diagnosis of CDI reduces transmission, prevents inadequate or unnecessary treatments, and assures best antibiotic treatment. We review the options for the laboratory diagnosis of CDI within the settings of the most accepted guidelines for CDI diagnosis, treatment, and prevention of CDI.

Real-Time Electronic Tracking of Diarrheal Episodes and Laxative Therapy Enables Verification of Clostridium difficile Clinical Testing Criteria and Reduction of Clostridium difficile Infection Rates

Health care-onset health care facility-associated Clostridium difficile infection (HO-CDI) is overdiagnosed for several reasons, including the high prevalence of C. difficile colonization and the inability of hospitals to limit testing to patients with clinically significant diarrhea. We conducted a quasiexperimental study from 22 June 2015 to 30 June 2016 on consecutive inpatients with C. difficile test orders at an academic hospital. Real-time electronic patient data tracking was used by the laboratory to enforce testing criteria (defined as the presence of diarrhea [≥3 unformed stools in 24 h] and absence of laxative intake in the prior 48 h). Outcome measures included C. difficile test utilization, HO-CDI incidence, oral vancomycin utilization, and clinical complications. During the intervention, 7.1% (164) and 9.1% (211) of 2,321 C. difficile test orders were canceled due to absence of diarrhea and receipt of laxative therapy, respectively. C. difficile test utilization decreased upon implementation from an average of 208.8 tests to 143.0 tests per 10,000 patient-days (P < 0.001). HO-CDI incidence rate decreased from an average of 13.0 cases to 9.7 cases per 10,000 patient-days (P = 0.008). Oral vancomycin days of therapy decreased from an average of 13.8 days to 9.4 days per 1,000 patient-days (P = 0.009). Clinical complication rates were not significantly different in patients with 375 canceled orders compared with 869 episodes with diarrhea but negative C. difficile results. Real-time electronic clinical data tracking is an effective tool for verification of C. difficile clinical testing criteria and safe reduction of inflated HO-CDI rates.

Is Follow-Up Testing with the FilmArray Gastrointestinal Multiplex PCR Panel Necessary?

The FilmArray gastrointestinal (GI) panel (BioFire Diagnostics, Salt Lake City, UT) is a simple, sample-to-answer, on-demand, multiplex, nucleic acid amplification test for syndromic diagnosis of infectious gastroenteritis. The aim of this study was to measure the yield of follow-up testing with FilmArray GI panel within 4 weeks of an initial test. Consecutive adult and pediatric patients tested at an academic institution between August 2015 and June 2016 were included in this study. Of 145 follow-up tests in 106 unique patients with an initial negative result, 134 (92.4%) tests and 98 (92.5%) patients remained negative upon follow-up testing. Excluding targets that are not reported at this institution (Clostridium difficile, enteroaggregative Escherichia coli, enteropathogenic E. coli, and enterotoxigenic E. coli), 137 (94.5%) follow-up tests and 101 (95.3%) patients remained negative. Weekly conversion rates were not significantly different across the 4-week follow-up interval. No epidemiological or clinical factors were significantly associated with a negative to positive conversion. Of 80 follow-up tests in patients with an initial positive result, 43 (53.8%) remained positive for the same target, 34 (42.5%) were negative, and 3 were positive for a different target (3.8%). Follow-up testing with FilmArray GI panel within 4 weeks of a negative result rarely changed the initial result, and the follow-up test reverted to negative less than half the time after an initial positive result. In the absence of clinical or epidemiological evidence for a new infection, follow-up testing should be limited and FilmArray GI panel should not be used as a test of cure.

Determining the cause of recurrent Clostridium difficile infection using whole genome sequencing

Understanding the contribution of relapse and reinfection to recurrent Clostridium difficile infection (CDI) has implications for therapy and infection prevention, respectively. We used whole genome sequencing to determine the relation of C. difficile strains isolated from patients with recurrent CDI at an academic medical center in the United States. Thirty-five toxigenic C. difficile isolates from 16 patients with 19 recurrent CDI episodes with median time of 53.5days (range, 13-362) between episodes were whole genome sequenced on the Illumina MiSeq platform. In 84% (16) of recurrences, the cause of recurrence was relapse with prior strain of C. difficile. In 16% (3) of recurrent episodes, reinfection with a new strain of C. difficile was the cause. In conclusion, the majority of CDI recurrences at our institution were due to infection with the same strain rather than infection with a new strain.

Reducing Unnecessary and Duplicate Ordering for Ovum and Parasite Examinations and Clostridium difficile PCR in Immunocompromised Patients by Using an Alert at the Time of Request in the Order Management System

We implemented hospital information system (HIS) alerts to deter unnecessary test orders for ovum and parasite (O&P) exams and Clostridium difficile PCR. The HIS alerts decreased noncompliant O&P orders (orders after >72 h of hospitalization) from 49.8% to 30.9%, an overall decrease of 19%, and reduced noncompliant C. difficile PCR orders (orders <7 days after a previous positive result) from 30.6% to 19.2%, an overall decrease of 31.9%.

Clinical characteristics of patients who test positive for Clostridium difficile by repeat PCR

The high sensitivity of PCR assays for diagnosing Clostridium difficile infection (CDI) has greatly reduced the need for repeat testing after a negative result. Nevertheless, a small subset of patients do test positive within 7 days of a negative test. The aim of this study was to evaluate the clinical characteristics of these patients to determine when repeat testing may be appropriate. The results of all Xpert C. difficile PCR (Cepheid, Sunnyvale CA) tests performed in the clinical microbiology laboratory at New York-Presbyterian Hospital, Columbia University Medical Center (NYPH/CUMC) from 1 May 2011 through 6 September 2013, were reviewed. A retrospective case-control study was performed, comparing patients who tested positive within 7 days of a negative test result to a random selection of 50 controls who tested negative within 7 days of a negative test result. During the study period, a total of 14,875 tests were performed, of which 1,066 were repeat tests (7.2%). Eleven of these repeat tests results were positive (1.0%). The only risk factor independently associated with repeat testing positive was history of a prior CDI (odds ratio [OR], 19.6 [95% confidence interval {CI}, 4.0 to 19.5], P < 0.001). We found that patients who test positive for C. difficile by PCR within 7 days of a negative test are more likely to have a history of CDI than are patients who test negative with repeat PCR. This finding may be due to the high rate of disease relapse or the increased likelihood of empirical therapy leading to false-negative results in these patients.