Simulated effects of ferritin screening on C‐reactive protein levels in recruited blood donors

BACKGROUND AND OBJECTIVES: Ferritin is commonly measured to evaluate iron stores in the body. Some countries have added or considered adding ferritin lower bounds to donor eligibility criteria. Ferritin is also elevated by inflammation. The main goal of this study is to estimate how different ferritin cut-offs would affect the proportion of donors with a C-reactive protein (CRP) level over 3 mg/L, which is the decision limit of the highest chronic cardiovascular risk. MATERIALS AND METHODS: To simulate recruitment of new blood donors, we selected participants from two Finnish general population cohorts, namely FINRISK 1997 (n = 5369) and Health 2000 (n = 3278), that would likely fulfil the selection criteria of blood donation. We then calculated the proportion of individuals with high-sensitivity CRP values above 3 mg/L, over a range of ferritin values. RESULTS: We found that for several ferritin cut-offs the proportion of potential donors with CRP > 3 mg/L would rise by a statistically significant amount. The trend was significant and similar for all subgroups but weaker for non-menstruating women as well as men. CONCLUSION: Our results show that screening a population of potential blood donors with ferritin cut-offs raises the number of people with CRP > 3 mg/L within the blood donor population.