Problems of Interpreting Diagnostic Tests for SARS-CoV-2: Analytical Chemistry Concerns

The COVID-19 pandemic outbreak made the development of reliable, sensitive, and reproducible testing methods crucial throughout the world. Without proper analytical validation, testing results can be misinterpreted, leading to a certain degree of misinformation in the clinical area. To accurately assess the methods, the determination of an analytical linear range of response of the assay is fundamental. Based on this curve, the evaluation of some parameters as sensitivity, limit of detection, and limit of quantification can be done, as well as the establishment of cut-off values. Statistical treatments of the collected data can be performed for reproducibility and reliability evaluations. In this context, there is a wide range of analytical concerns that should be in-depth discussed in medical, biomedical and chemical areas. This letter aims to briefly clarify some analytical chemistry concepts, as sensitivity, cut-off and limit of detection, and their application towards clinical diagnosis.