Haemoglobin trajectories

November 2015

170x145-Hb-metingCan different haemoglobin trajectories be distinguished in blood donors? Blood donors are prone to iron deficiency, as blood donation implies a loss of iron. In donors with sufficient iron stores this may not be problematic, however repeated donations could deplete iron stores and lead to anemia. Distinguishing between donors with different haemoglobin trajectories after repeated blood donations may help to select donors and tailor their donation intervals to prevent anemia.

Sanquin, the national blood service in the Netherlands uses guidelines regarding Haemoglobin (Hb) levels and donation intervals in order to maintain donor health. The minimum donation interval is 56 days, with a yearly maximum of 5 donations for men and 3 for women. However, recent and historical data suggest that individual donors may differ in their recovery from blood donation, and that a donation interval of 56 days may not be desirable for each individual donor. For some donors this interval might be too short, resulting in gradually declining Hb levels over time, which are currently not detected until the donor meets any of the deferral criteria (capillary Hb levels below 8.4 mmol/l for men, below 7.8 mmol/l for women, or 1.5 mmol/l below their previous Hb level). Deferrals can be demoralizing for donors and have a negative effect on donor return rates. 

Distinguishing between donors with different Hb trajectories after repeated blood donations may help to select donors and tailor their donation intervals to prevent anemia and donor deferral. Therefore, we investigated whether different Hb trajectories can be distinguished in blood donors. Furthermore, we determined whether the type of trajectory was associated with the probability of deferral due to low Hb levels. Finally, we aimed to predict the type of Hb trajectory of a newly registered blood donor.

Latent class growth analyses, stratified by sex, were applied to 5,388 donors (1,902 men) who registered as new donor after 2004 and participated in Donor InSight I and/or II. Four groups of donors were identified for both, men and women. Stable Hb trajectories were found among 14% of men and 15% of women, while declining Hb trajectories after successive blood donations were observed in the remaining groups of donors. Donor deferrals differed strongly between the groups, with donors in groups with a relatively low initial Hb level being deferred more frequently than donors in the other groups. Last, initial Hb levels and age can predict Hb trajectory.

These findings are of high importance for identification of donors who could benefit from tailored donation intervals in order to prevent iron deficiency and donor deferrals. For example, donors with a declining Hb trajectory could be recommended to prolong their donation interval.

This study was supported by Sanquin Blood Supply. The full article can be found at http://onlinelibrary.wiley.com/doi/10.1111/trf.13066/abstract.

Last edited on: 2 November 2015