Iron Store Depletion with Increasing Donation Frequency despite Normal Haematological Indices: A Multicentre Cross-Sectional Study in Ilorin, Kwara State, Nigeria

Abstract

Repeated blood donation is a major cause of progressive iron store depletion, yet routine donor screening often fails to detect early iron deficiency. This study evaluated the effect of donation frequency on iron status among blood donors in Ilorin, Kwara State, Nigeria, and assessed the utility of haematological indices as surrogate markers of iron depletion where ferritin testing is unavailable. A multicentre cross-sectional study was conducted among 270 eligible blood donors from ten hospitals across Ilorin metropolis. Participants comprised 72 first-time and 198 repeat donors, stratified into low- (2-3/year), moderate- (4-6/year), and high-frequency (>6/year) groups. Haematological parameters were assessed using the Mindray BC-10 analyser. Serum iron and total iron-binding capacity were quantified using an automated chemistry analyser, while ferritin and transferrin were determined by ELISA. Transferrin saturation (TSAT) was calculated mathematically. Data were analysed using SPSS 27.0 at p<0.05. Haemoglobin, packed cell volume, red blood cell count, and red cell indices showed no significant differences across donation-frequency groups (p>0.05). However, serum iron, ferritin, transferrin, and TSAT declined significantly with increasing donation frequency (p<0.05). Mean ferritin decreased from 138.4±36.4 ng/mL in first-time donors to 63.2±22.5 ng/mL in high-frequency donors, while TSAT fell from 30.1±9.2% to 10.1±4.5%, respectively. Correlations between iron parameters and red cell distribution width (RDW)/mean corpuscular haemoglobin concentration (MCHC) suggest early subclinical erythrocyte changes. Repeated donation is associated with frequency-dependent iron depletion despite normal haematological indices. Routine ferritin monitoring, or RDW/MCHC-based risk flagging, should be incorporated into donor management to protect donor health and blood supply integrity.