ELP1 and Fabry disease: An ELP1 threshold of 492 pg/mL yielded a sensitivity of 80.2% (CI of 70.6 to 87.2%) and a specificity of 98.2% (95% CI of 90%-99%) with a positive likelihood ratio of 46.5, indicating that individuals with FD were over 46 times more likely to have ELP1 levels below this threshold compared to non-affected carriers.<h4>Conclusion</h4>Blood ELP1 levels are robust and reproducible, with concentrations below 492 pg/mL strongly indicative of disease.