Pediatric decision limits for serologic screening of Lyme disease
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Published on: July 14, 2023
Oscar Lopez-Nunez1, Pooja Srivastava1, Bradley J Wheeler2
1Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Insights
New Lyme disease (LD) testing ranges for children reduce equivocal results and overdiagnosis. This study establishes pediatric-specific serology cutoffs for more accurate Lyme disease diagnosis in children.
Area of Science:
- Medical Diagnostics
- Pediatric Infectious Diseases
- Clinical Laboratory Science
Background:
- Laboratory diagnosis of Lyme disease (LD) typically uses a two-tier serological protocol.
- Manufacturer-provided ranges, based on adult studies, lead to high rates of equivocal results in pediatric patients.
- This necessitates further testing, increasing diagnostic uncertainty and healthcare costs.
Purpose of the Study:
- To determine appropriate serological ranges for Lyme disease testing in a pediatric population.
- To reduce the disproportionate number of equivocal results in children using standard adult ranges.
- To improve the accuracy and efficiency of Lyme disease diagnosis in pediatric patients.
Main Methods:
- A retrospective review of 2755 pediatric LD tests using Vidas® Lyme IgM II/IgG II immunoassays was conducted.
- Results were analyzed using frequency distributions and percent agreement analysis.
- Clinical adjudication was used to validate the proposed optimized ranges.
Main Results:
- Modified ranges decreased the IgM equivocal rate from 7% to 2% and the IgG positive rate from 15% to 13%.
- Positive percent agreement between IgM and IgG testing decreased, while negative and overall percent agreements increased.
- Reclassification of serologies based on new ranges showed improved correlation with clinical assessments.
Conclusions:
- The proposed modified serological ranges are better suited for the pediatric population.
- These new ranges effectively reduce overdiagnosis, unnecessary treatment, and diagnostic uncertainty.
- Implementation of these ranges can lead to improved diagnostic efficiency and reduced turnaround times for pediatric Lyme disease testing.
Background:
Laboratory diagnosis of Lyme disease (LD) relies on a two-tier protocol. We have observed disproportionate equivocal serologies in children requiring reflex western blot (WB) using manufacturer-provided ranges based on adult studies. We aimed to determine appropriate ranges for our pediatric population.
Methods:
We performed a one-year retrospective institutional review of all 2755 children with LD testing with the Vidas® Lyme IgM II/IgG II immunoassays with reflex to WB for equivocal/positive serologies. Results were assessed by frequency distributions, optimization via percent agreement analysis, and clinical adjudication.
Results:
The proposed ranges for IgM (negative ≤0.20, equivocal ≥0.21 to <0.32, positive ≥0.32) and IgG (negative ≤0.50, positive >0.50) allowed for a decrease in the IgM equivocal rate (7% to 2%) and IgG positive rate (15% to 13%). There was a decrease in the positive percent agreement between tiers (95% to 83% and 98% to 95%) with increase in the negative (32% to 63% and 70% to 81%) and overall (65% to 73% and 85% to 88%) percent agreements for IgM and IgG, respectively. Of 15 IgM serologies reclassified as negative with a positive WB and not positive for IgG, 8 were clinically negative, 5 were clinically positive, and two had insufficient history. Of the 10 IgG serologies reclassified as negative with a positive WB 3 were clinically positive, 6 were clinically negative and one had insufficient history.
Conclusions:
Our modified ranges are more suitable for our pediatric population while reducing overdiagnosis, unnecessary treatment, diagnostic uncertainty, and turnaround time.
