Background: Iron deficiency anemia (IDA) is the most common type of anemia worldwide and has many adverse effects on life quality. This meta-analysis study aims to show that reticulocyte hemoglobin content (CHr) is more effective than routinely used parameters in the diagnosis of IDA. Methods: Comprehensive and systematic research was done using international databases including PubMed, Web of Science, Cochrane Library, Science Direct, and Google Scholar, which contain all articles published on IDA until December 29, 2020. Seventeen articles were included in the meta-analysis. Results: The analyses found the Cohen's deffect size (Standardized Mean Difference) values of the parameters. Accordingly, CHr is 2.84 (95% CI 2.36 to 3.31), mean corpus volume (MCV) is 2.46 (95% CI 1.97 to 2.95), ferritin is 2.37 (95% CI 1.63 to 3.11), and transferrin saturation (TSAT) is 3.76 (95% CI 2.14 to 5.38). To diagnose IDA, the sensitivity value of the CHr concentration was found as 83.5% (95% CI 76.1 to 89.8), specificity value to be 91.8% (95% CI 85.5 to 96.4), and mean cut-off value as 28.2 pg. Conclusions: The results of our study reveal the findings that CHr is a better biomarker than MCV and ferritin used in determining IDA, and its efficacy is lower than TSAT. It is very important to use it routinely for the pre-diagnosis of IDA, which is very important for public health. The groups in the study are heterogeneous but contain bias. Therefore, meta-analyses of studies with less heterogeneity of CHr are needed.

Background: This study investigated the relationship between erythrocyte membrane fatty acids, omega-3 index, and zinc protoporphyrin (ZnPP) levels in hemodialysis (HD) patients across hemoglobin-defined anemia severities. Methods: This prospective cross-sectional study included 117 chronic HD patients and 28 healthy controls. ZnPP was measured by high-performance liquid chromatography, and erythrocyte membrane fatty acids by gas chromatography–mass spectrometry. Results: HD patients showed a significantly lower omega-3 index than controls (p < 0.0001), although it did not differ across hemoglobin-defined groups (p = 0.589). Palmitic and erucic acid were higher, whereas oleic acid was lower, in patients with lower hemoglobin. In unadjusted analyses, hemoglobin correlated inversely with palmitic acid (r = −0.220, p = 0.017) and erucic acid (r = −0.183, p = 0.048), whereas the positive association with oleic acid (r = 0.451, p < 0.0001) remained significant after false discovery rate (FDR) correction. ZnPP increased as hemoglobin decreased (p = 0.013) and was negatively associated with hemoglobin (r = −0.406, p < 0.0001). Conclusions: HD patients with lower hemoglobin showed altered erythrocyte membrane fatty acid composition; among fatty acids, only the oleic acid–hemoglobin association remained significant after FDR correction. ZnPP rose as hemoglobin declined and was independently inversely associated with hemoglobin after multivariable adjustment (β = −0.051, p < 0.0001), independent of any dichotomous reference definition, supporting ZnPP as a continuous marker of anemia severity and iron-restricted erythropoiesis in HD patients.

Background: This study aimed to evaluate the potential of microRNA (miRNA)-210 as a biomarker for distinguishing iron deficiency anemia (IDA) from functional iron deficiency (FID) in hemodialysis (HD) patients. The diagnostic performance of miRNA-210 was also compared with conventional biochemical markers, including hemoglobin (Hb), ferritin, transferrin saturation (TSAT), and zinc protoporphyrin (ZnPP). Methods: Fifty HD patients were classified into control, IDA, and FID groups according to Hb, ferritin, and TSAT criteria. Pre-dialysis blood samples were collected, and plasma miRNA-210 levels were measured using reverse transcription quantitative polymerase chain reaction (RT ² -PCR). Diagnostic performance was assessed through receiver operating characteristic (ROC) analysis alongside traditional biomarkers. Results: Plasma miRNA-210 levels were significantly higher in the IDA group compared to both the control ( p = 0.0010) and FID ( p = 0.0007) groups. A significant negative correlation was observed between miRNA-210 and Hb ( ρ = −0.363, p = 0.0155). ROC analysis showed that miRNA-210 had moderate diagnostic discriminatory ability for differentiating IDA (AUC = 0.711, p = 0.0186). Its performance was comparable to ZnPP and exceeded to ferritin and TSAT. Conclusion: miRNA-210 may serve as a supportive biomarker, reflecting the interaction between hypoxia and iron metabolism in distinguishing IDA from FID among HD patients. These findings indicate that miRNA-210 could provide additional value in understanding anemia pathophysiology and enhance diagnostic evaluation. Limitations: Key limitations include the small sample size, single-center, cross-sectional design, absence of a healthy control group, and lack of molecular-level functional validation. Larger multicenter studies are needed to confirm these findings and determine clinically relevant cut-off values for miRNA-210.