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D-Dimer Varies Widely Across Instrument Platforms and is Not a Reliable Indicator of Periprosthetic Joint Infections
Lauren N Pearson1, Karen A Moser1, Robert L Schmidt1
1Department of Pathology, ARUP Laboratories & University of Utah, Salt Lake City, UT, USA.
Abstract:
The D-dimer test is a component of the modified scoring criteria for periprosthetic joint infection (PJI). The performance of the D-dimer test varies greatly among laboratories because of the lack of standardization. Laboratories may use different assays and will produce widely varying results for the same sample. This study used published proficiency testing data from 3903 laboratories to demonstrate the variability in D-dimer results and estimate the misclassification rate of patients using the proposed cutoff for the test as a component of PJI criteria. Given the variability in D-dimer results, a clinically significant percentage of patients are likely to be misclassified. The data illustrate that a universal cutoff for this marker in the context of assessment for PJI is not appropriate. Each site must conduct a study to determine an appropriate cutoff for their unique testing platform.
Insights
The D-dimer test shows significant variability across labs, potentially misclassifying patients with periprosthetic joint infection (PJI). A universal cutoff is inappropriate; each lab needs a site-specific D-dimer threshold for accurate PJI diagnosis.
Area of Science:
- Biomedical diagnostics
- Clinical chemistry
- Orthopedic surgery
Background:
- The D-dimer test is utilized in diagnostic criteria for periprosthetic joint infection (PJI).
- Standardization issues with D-dimer assays lead to significant inter-laboratory performance variation.
- This variability impacts the reliability of D-dimer results in clinical decision-making for PJI.
Purpose of the Study:
- To assess the variability of D-dimer test results across numerous laboratories.
- To estimate the potential misclassification rate of patients with PJI due to D-dimer assay variability.
- To evaluate the suitability of a universal D-dimer cutoff for PJI diagnosis.
Main Methods:
- Analysis of published proficiency testing data from 3903 laboratories.
- Statistical evaluation of D-dimer result variability.
- Estimation of patient misclassification rates based on proposed PJI criteria cutoffs.
Main Results:
- Demonstrated substantial variability in D-dimer results among participating laboratories.
- Indicated a clinically significant percentage of patients are likely to be misclassified.
- Highlighted the inappropriateness of a universal D-dimer cutoff for PJI assessment.
Conclusions:
- The significant inter-laboratory variability of the D-dimer test precludes a universal cutoff for periprosthetic joint infection (PJI) diagnosis.
- Site-specific studies are essential to establish appropriate D-dimer cutoffs for individual testing platforms.
- Accurate PJI diagnosis requires addressing D-dimer assay standardization and establishing localized reference ranges.
