The challenges of managing donor haemoglobin

Abstract

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 HemoCueÒ 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 ...

Hemoglobina reticulocitaria en donantes de sangre repetitivos, que acuden al banco de sangre de la Escuela de Microbiología de la Universidad de Antioquia

“…La deficiencia temprana de hierro comúnmente no se acompaña de anormalidades en el hemograma ni cambios morfológicos en el extendido de sangre periférica, se caracteriza por ferritina sérica baja y hemoglobina normal, condiciones que cambian en el momento que se instaura la anemia (15) , es por ello que el diagnóstico incluye varias pruebas que requieren una adecuada interpretación dado el gran número de moléculas que participan en su metabolismo. Algunas de ellas se alteran por otros estados patológicos como la infección o la inflamación, dentro de los ensayos se encuentra el hierro medular; considerado el estándar de oro para definir la deficiencia absoluta de hierro, ya que permite la búsqueda de sus depósitos en la médula ósea mediante la coloración de azul de Prusia, sin embargo, en la actualidad ha perdido uso debido al tipo de muestra que se emplea y a que es una técnica que en gran medida depende del observador (2) ; otras pruebas usadas para detectar deficiencia de este nutriente son el hierro sérico, la transferrina, el receptor soluble de transferrina, la ferritina y la hepcidina (15)(16)(17)(18) , sin embargo, y pese a este panorama de opciones diagnósticas en los bancos de sangre se tamiza la anemia sólo por medio de la medición de hemoglobina, más no se ha establecido un examen de seguimiento eficaz y económico en los donantes, que garantice que los niveles de hierro perdidos no afecten las funciones metabólicas de éste; aunque donar sangre trae consigo beneficios, si se hace de manera repetitiva puede ocasionar deficiencia de hierro y finalmente un cuadro anémico (19) . En consonancia con lo anterior, es importante explorar alternativas que permitan determinar precozmente estados de déficit de hierro en el contexto del banco de sangre, si bien se cuenta con varios biomarcadores, éstos conllevan a un mayor costo y tiempo de análisis.…”