F2 and Thrombocytosis: When conducting multivariate regression analysis, it was found that the predictors of the development of post-COVID syndrome are the presence of a history of obesity and allergic pathology, fever during the acute phase of the disease or a total number of symptoms of 3 or more, as well as laboratory parameters, in particular thrombocytosis, neutrophilia, changes in prothrombin time and a decrease in serum vitamin D levels.