Haemoglobin screening has long provided blood services with a means to determine the eligibility of prospective donors. Screening aims to protect donors from donating whilst anaemic, minimise the risk of anaemia developing as a result of donation and ensure an adequate red cell component for the transfusion recipient.
Addressing the limitations, risks and benefits of haemoglobin screening to both donor and recipients requires continuous surveillance and an evidence-based response to evolving clinical research and technological innovations. Challenges include determination of appropriate thresholds in specific populations, management of donors with low haemoglobin, realising the limitations of haemoglobin as a predictor of iron status, and the assessment and selection of alternative screening devices.
Current haemoglobin thresholds are now in doubt, with recent large US population studies re-defining normal ranges for haemoglobin. A further confounding factor is local and international research highlighting the significant prevalence of iron deficiency in eligible donor populations. This reinforces the limitations of haemoglobin as a stand-alone point of care screening test.
Current practice at the Australian Red Cross Blood Service (Blood Service) to assess donor haemoglobin involves a pre-donation capillary finger prick sample analysed on the HemoCue® 201+. Minimum thresholds for whole blood donation are 120 and 130 g/l for females and males respectively. Donors with low haemoglobin are deferred, offered ferritin testing, and referred to their GP for management if subsequently identified as anaemic and/or iron deficient.
The management of low haemoglobin deferrals is currently under review. These account for 16% of all deferrals. Routine ferritin testing of low haemoglobin-related deferrals indicates 75% are associated with iron deficiency, with approximately 60% in females aged ≤50 years. Local research indicates a substantial loss of donations due to delayed or non-return following a low haemoglobin deferral. Additional local research suggests that screening with haemoglobin and iron indices enables prediction of donors at risk of subsequent anaemia and who would most benefit from prevention strategies.
Technological advances may allow additional means by which to improve donor experience and safety. These include the use of a more palatable non-invasive haemoglobin analyser, and point of care ferritin testing, both of which are to be assessed by the Blood Service for accuracy and feasibility of implementation.
The greatest challenge is to manage the balance of donor health and well-being with the potential supply loss from healthy donors. To optimise donor iron status and subsequently improve efficiency and supply through reduced deferrals and improved return rates, the Blood Service is considering a comprehensive targeted strategy. Options include improving informed decision-making for donors, education, ferritin screening, donation frequency modification and/or iron supplementation. Our recently completed randomised, double blind trial of carbonyl iron supplementation in premenopausal female blood donors will be a valuable resource in the development of this strategy. Initiatives need to be responsive to the needs and expectations of donors, community and health professionals, whilst considering the immediate and long-term impacts on inventory and logistics of implementation. The Blood Service has established a cross-functional Iron Taskforce to scope and develop such strategies.