## 2 Materials and Methods
More than 98% of the oxygen in the blood is bound to HB, which in turn circulates in the blood stream and is allocated within the red blood cells. Without hemoglobin, erythrocytes would not be able to fulfill their task as oxygen carriers in the blood. Altered hemoglobin levels can be a consequence of, among others, heart disease, chronic lung disease, iron deficiency, and anemia [34]. White blood cells are cells of the immune system involved in protecting the body from infection and other diseases. An excess of white blood cells is usually due to an infection or inflammation. Less commonly, an elevated white blood cell count may indicate certain blood cancers or bone marrow disorders. Several types of white blood cells, including neutrophils and lymphocytes, are responsible for the fight against infections caused by bacteria and fungi, the antibody response, and the fight against virus-infected and tumor cells [35]. Platelets are a blood component whose task is to intervene in the event of a blood vessel injury [36]. Their main function is to intervene in the event of endothelium rupture by participating in the formation of a platelet plug. In addition, platelets participate in intravascular immune responses [37; 38]. The platelet-lymphocyte ratio is an inflammatory marker that can be used to predict inflammation and mortality in some diseases. The platelet-lymphocyte ratio can be influenced by various inflammatory conditions, such as atherosclerosis, platelet activation, or an elevated inflammatory state [39]. Vitamin D is a fat-soluble secosterol. It is responsible, among other things, for the homeostasis and metabolism of calcium, magnesium, and phosphate and for many other biological effects [40]. Albumin is a member of a family of globular and transport proteins, whose main functions are the regulation of blood oncotic pressure; the binding of vitamin D, its metabolites, and fatty acids; and the regularization of bone mineralization [41]. Total protein is a clinical parameter that indicates the concentration of protein in the serum. Detecting the amount of protein in serum is a diagnostic and clinical monitoring tool [42]. CRP is a protein present in blood plasma, the concentration of which increases in response to an acute or chronic inflammatory phenomenon, such as rheumatic diseases, infections (bacterial, viral, or fungal), neoplasms, and tissue lesions [43]. Procalcitonin is a precursor peptide of the hormone calcitonin, the latter being involved in calcium homeostasis. Its level increases following a pro-inflammatory stimulus, especially if it is of bacterial origin [44]. The mBI is an ordinal scale that assesses a person's independence in completing activities of daily living (ADL). Eleven ADLs are considered: feeding, dressing/undressing (clothing), personal hygiene, bathing/showering, bowel sphincter control, bladder sphincter control, chair to bed and back movements, toilet use (getting in and out of the toilet), mobility (walking on level ground), wheelchair use, and climbing and descending stairs. Each score can be assigned a value from 0 to 15, depending on the activity. There are five levels to take into account: (i) complete inability to perform the task (even with help); (ii) need for significant help to complete the task; (iii) need for moderate help and/or active supervision to complete the task; (iv) need for minimal help and/or passive supervision, i.e., the presence of someone even without active intervention; (v) ability to complete the task independently. Higher scores correspond to a greater degree of independence in performing the ADL [45]. The HGT is an instrument for measuring the maximum isometric force of the muscles of the upper limb. The test is performed with a dynamometer that records the force variations of each candidate. The patient is asked to squeeze the dynamometer as tightly as possible and maintain the contraction for at least 5 s, then release the muscles and evaluate the results.