Communication regarding the article "An efficient primary screening COVID-19 by serum Raman spectroscopy".

When performing computational modeling and machine learning experiments, it is imperative to follow a protocol that minimizes bias. In this communication, we share our concerns regarding the article "An efficient primary screening COVID-19 by serum Raman spectroscopy" published in this journal. We consider that the authors may have inadvertently biased their results by not guaranteeing complete independence of test samples from the training data. We corroborate our point by reproducing the experiment with the available data, showing that if full independence of the test set was ensured, the reported results should be lower. We ask the authors to provide more information regarding their article, as well as making available all code used to generate their results. Our experiments are available at https://doi.org/10.6084/m9.figshare.14124356.