Related Experiment Video
Updated: Jun 20, 2026
A Protocol to Characterize the Morphological Changes of Clostridium difficile in Response to Antibiotic Treatment
Published on: May 25, 2017
Are We Moving Toward Diagnostic Stewardship Or Laboratory Retrogress On Clostridioides difficile Testing?
Dhammika H Navarathna1, Lisa Cornelius2, Janell Lukey1
1Department of Pathology and Laboratory Medicine Services, Central Texas Veterans Health Care System, Temple, TX, USA.
Abstract:
The widespread adoption of PCR-based testing for Clostridioides difficile infection (CDI) has replaced enzyme immunoassays (EIA) in the U.S., increasing sensitivity and reported healthcare-onset CDI (HO-CDI) cases. However, concerns about overdiagnosis persist, as PCR may detect asymptomatic colonization. To mitigate this, some institutions use a 2-step algorithm, confirming positive PCR/GDH results with EIA. Our healthcare system, which exclusively reports PCR results, conducted a process improvement (PI) project to evaluate whether incorporating EIA testing could improve hospital reporting and patient safety. We compared our routine PCR testing with 2 commercial EIA platforms to assess sensitivity and specificity and analyzed PCR cycle threshold (Ct) values in relation to EIA results. EIA tests demonstrated less than 30% sensitivity compared to PCR, artificially reducing HO-CDI cases. Few inpatients tested by PCR despite not meeting CDI testing criteria had positive EIA results, indicating true CDI and highlighting the need for better provider education. Lower PCR Ct values, reflecting higher bacterial loads, correlated with EIA positivity, suggesting that EIA requires higher toxin expression for detection. Implementing decision-making alerts in electronic ordering improved diagnostic stewardship. While multi-step testing algorithms may reduce HO-CDI rates, they risk excluding toxin-negative (false-negative) CDI due to EIA's low sensitivity. This approach offers limited clinical value in CDI management. Instead, reinforcing provider education on appropriate testing criteria is a more effective strategy to reduce unnecessary testing and improve patient care.
Insights
Enzyme immunoassays (EIA) show low sensitivity for detecting Clostridioides difficile infection (CDI) compared to PCR. Relying solely on EIA may miss cases, emphasizing the need for provider education on appropriate CDI testing criteria.
Area of Science:
- Clinical microbiology
- Infectious disease diagnostics
- Healthcare quality improvement
Background:
- Polymerase chain reaction (PCR) testing for Clostridioides difficile infection (CDI) has largely replaced enzyme immunoassays (EIA) in the U.S.
- While PCR offers higher sensitivity, concerns about overdiagnosis due to detection of asymptomatic colonization persist.
- Some institutions employ a two-step algorithm using EIA to confirm positive PCR results, aiming to mitigate overdiagnosis.
Purpose of the Study:
- To evaluate the impact of incorporating EIA testing into a PCR-exclusive system within a healthcare setting.
- To assess the sensitivity and specificity of commercial EIA platforms compared to routine PCR testing for CDI.
- To determine if EIA confirmation could improve hospital reporting and patient safety regarding healthcare-onset CDI (HO-CDI).
Main Methods:
- Comparison of routine PCR testing with two commercial EIA platforms for CDI detection.
- Analysis of PCR cycle threshold (Ct) values in relation to EIA results.
- Evaluation of the impact of electronic ordering alerts on diagnostic stewardship.
Main Results:
- EIA demonstrated less than 30% sensitivity compared to PCR, leading to an artificial reduction in reported HO-CDI cases.
- A small number of inpatients with positive EIA results, despite not meeting initial testing criteria, indicated true CDI, highlighting potential gaps in provider education.
- Lower PCR Ct values (higher bacterial load) correlated with EIA positivity, suggesting EIA's requirement for higher toxin levels for detection.
Conclusions:
- Multi-step testing algorithms using EIA may decrease HO-CDI rates but risk missing true CDI cases due to EIA's low sensitivity.
- The clinical utility of EIA in CDI management is limited.
- Enhancing provider education on appropriate CDI testing criteria is a more effective strategy to reduce unnecessary testing and improve patient care.
Related Concept Videos
01:24Automated Microbial Diagnostics
01:25Rapid Identification of Pathogens
01:30Inflammatory Bowel Disease III: Diagnostic Studies and Management I-Nutritional Therapy
Diagnostic studies
A colonoscopy is the definitive screening test, distinguishing ulcerative colitis from other colon diseases with similar symptoms. During a colonoscopy test, inflamed mucosa with exudate ulcerations can be observed, and biopsies are taken to determine the histologic characteristics of the colonic...
01:30Serum Laboratory Studies, Stool Test, Breath Test
01:30Urinary Tract Infection III: Diagnostic Studies and Interprofessional Care
01:26Urine Studies II: Urine Culture and Sensitivity Test