Changes in Laboratory Indicators of Anemia Depending on the Stages of Chronic Kidney Disease

The progression of chronic kidney disease (CKD) is characterized by the irreversible reduction of nephron mass and homeostatic dysfunction, notably the development of severe renal anemia. This study aims to quantitatively evaluate laboratory shifts in the hematopoietic system proportional to the declining stages of the estimated glomerular filtration rate (eGFR). Within a prospective observational framework, the hematological and biochemical parameters of 145 patients in CKD stages 3-5 were analyzed. The outcomes confirmed a strict direct correlation (r = 0.72, p < 0.001) between eGFR indices and endogenous serum erythropoietin (EPO) levels. While mild normocytic anemia (Hb 108.5 ± 7.2 g/L) predominated in stage 3, the terminal stage 5 demonstrated the formation of severe, aregenerative anemia (Hb 78.6 ± 5.4 g/L) driven by a critical decline in EPO synthesis (6.2 ± 1.8 mIU/mL). The integral monitoring of hematological indicators alongside eGFR dynamics establishes a highly sensitive objective substrate for the early stratification of nephrological patients and the timely personalization of erythropoiesis-stimulating therapy.