2.2. 
To gain insights into possible differences in The optimal model complexity was found to be 3 ± 1 latent variables and yielded an average classification accuracy of 80.2 ± 3.0%, corresponding to 78.1 ± 3.2% and 88.9 ± 5.2% correct classification rate for participants with long COVID and controls, respectively. The non-parametric estimation of the distribution of these figures of merit under the null hypothesis by permutation testing indicated that they were statistically significant (A graphical representation of the discriminant ability of the model is depicted in Inspection of the contribution of individual According to reference values proposed by major clinical medical laboratories [In participants with long COVID, lower circulating levels of 