## 4 Methods
### Dataset
* _Mean corpuscular hemoglobin_ **MCH**: It is the average amount in each red blood cell of a protein called hemoglobin, which carries oxygen around one's body [4], and variation may be indicative of COVID-19, as reported by [66]. A low MCH value typically can indicates the presence of iron deficiency anemia. In general, patients with COVID-19 will present with slightly lower values within a standard deviation of the norm. * _Mean corpuscular hemoglobin concentration_ **MCHC**: It is similar to MCH, as MCHC is a measure of the average concentration of hemoglobin inside a single red blood cell [4]. A low MCHC shows that someone's red blood cells do not have enough hemoglobin, in part suggesting anemia. In [67], this is one of the parameters that allowed differentiating cases of COVID-19 from community-acquired pneumonia. * _Mean corpuscular volume_ **MCV**: Average size (volume) of red blood cells [4]. An increase or decrease in the average volume of red blood cells can indicate several health problems, and there are studies that have related this variation to the severity of COVID-19 [61; 66]. * _Lymphocytes absolute_: Indicator of infectious processes. A low value may represent severe COVID-19, leading to early treatment or poor prognosis, according to [62];
* _Leukocytes_: White blood cells are defense cells of the immune system. It has also been identified that the COVID-19 virus can attack these cells, causing them to secrete pro-inflammatory cytokines, increasing the inflammatory status of the patient [68; 69]. It is also possible to analyze markers in the genomes of white blood cells as identifiers of COVID-19 [70]. * _Basophils absolute_: Basophils are important cells in the human immune system and are normally increased in cases of allergy or prolonged inflammation. Studies indicate that they are decreased significantly in cases of infection with COVID-19, especially cases with greater severity, according to studies in [71; 72]. * _Eosinophils absolute_: They are also part of the human immune system and are responsible for the body's defense against parasites and infectious agents. Like basophils, their count decreases in cases of COVID-19, according to studies in [73; 74]. * _Platelets_: They are blood cells produced by the bone marrow and are responsible for the blood clotting process. This indicator should be observed carefully, as its increase does not indicate COVID-19, but may indicate complications triggered by the disease, such as thrombosis, according to [75]. * _Monocytes absolute_: According to [76], _monocytes_, and _macrophages_, are part of the body's immune system and are responsible for providing immune defense against a wide variety of microorganisms and viruses. While _macrophages_ reside in body tissues, _monocytes_ circulate throughout the body through the bloodstream and can be detected in blood counts. The author also pointed out that, despite being beneficial, these cellshave unfavorable effects on those infected with COVID-19, generating lesions and infections in the lung. Reference [76] reports that several studies point to a reduction in the number of _monocytes_ in cases of COVID-19 infection. Studies such as [77] propose that new techniques be developed to identify the migration of these cells to the lung as a possible indicator of COVID-19 and the use of some therapies to reduce the damage caused to the organ. * SARS_CoV2_PCR: According to [76], **RT-PCR** is an indicative test for confirmation of infection with COVID-19 because it detects the presence of the genetic material of the virus. This variable will receive the values (labels) 0 for negative cases and 1 for positive cases.