Determination of integrated optical density of hemoglobin derivatives for comprehensive assessment of anemia risk in postpartum women after COVID-19

Introduction. The relevance of this study stems from the need to evaluate the impact of COVID-19 on the blood oxygen transport system in women infected during pregnancy.

Aim. To determine the integrated optical density (IOD) of hemoglobin derivatives as part of a comprehensive assessment of anemia risk in postpartum women following SARS-CoV-2 infection.

Materials and methods. The study included 76 postpartum women (main group) infected with SARS-CoV-2 during the third trimester of pregnancy: 46 with mild COVID-19 (subgroup 1) and 30 with moderate disease (subgroup 2). The control group consisted of 33 women with no history of COVID-19 before or during pregnancy. Hemoglobin concentration and erythrocyte count were measured using the automated hematology analyzer Mindray BC- 5150. Induced optical density (IOD) of hemoglobin derivatives was assessed using the automated microscopy system "MEKOS-Ts2".

Results. A severity-dependent reduction in erythrocyte count and hemoglobin concentration was observed. Compared to controls, erythrocyte counts decreased by 1.13-fold (subgroup 1) and 1.23-fold (subgroup 2) (p < 0.001), while hemoglobin levels declined by 1.13-fold and 1.24-fold, respectively (p < 0.001). Subgroup 2 showed significantly lower values than subgroup 1 (by 1.09- and 1.10-fold, respectively; p < 0.001). IOD analysis revealed reduced oxyhemoglobin (HbO2) in subgroups 1 and 2 by 1.61- and 1.92-fold (p < 0.001), and deoxyhemoglobin (HHb) by 1.52-fold (p = 0.007) and 1.89-fold (p < 0.001), respectively, versus controls, with no significant difference between subgroups. Methemoglobin (MetHb) IOD increased by 1.54-fold (subgroup 1) and 1.76-fold (subgroup 2) compared to controls (p < 0.001); the difference between subgroups was 1.14-fold (p = 0.028). Significant inverse correlations were found between hemoglobin levels and MetHb IOD in both subgroups (ρ = –0.81 and ρ = –0.90; p < 0.01), described by linear regression equations—indicating that hemoglobin decline was accompanied by MetHb IOD elevation. ROC analysis confirmed that elevated MetHb IOD is a prognostically significant predictor of anemia (AUC = 0.820; 95% CI: 0.708–0.932; p < 0.001), with a cutoff value of 16.59 µm2, sensitivity of 75%, and specificity of 79%.

Conclusion. Combined analysis of hemoglobin derivatives’ IOD and hematological parameters enables assessment of the oxygen transport system status and elucidates mechanisms underlying anemia development in postpartum women after COVID-19. Incorporating these parameters into clinical practice will allow precise risk stratification and personalized patient management.

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