Predictors of low haematocrit among repeat donors in São Paulo, Brazil: Eleven year longitudinal analysis Fernanda N. Almeida a , Ester C. Sabino b,c,⇑ , Gisela Tunes d , George B. Schreiber b , Pedro Paulo S.B. da Silva a , Anna Barbara F. Carneiro-Proietti e,f , João Eduardo Ferreira a , Alfredo Mendrone-Junior b a Laboratório de Banco de Dados, Universidade de São Paulo, São Paulo, Brazil b Fundação Pró-Sangue/Hemocentro de São Paulo, São Paulo, Brazil c Departamento de Doenças Infecciosas e Parasitarias/Instituto de Medicina Tropical-Universidade de São Paulo, São Paulo, Brazil d Departamento de Estatística, Universidade de São Paulo, São Paulo, Brazil e Fundação Hemominas, Minas Gerais, Brazil f Faculdade de Ecologia e Saúde Humanas (FASEH), Minas Gerais, Brazil article info Article history: Received 28 February 2013 Received in revised form 23 August 2013 Accepted 20 September 2013 Keywords: Haematocrit Anaemia Blood donors Qualifying donation Blood donation abstract Background and Objectives: Few longitudinal studies have examined the long-term effect on deferral for low haematocrit (Hct) or haemoglobin, indicators of presence of anaemia. This study retrospectively analysed 11 years of donation history to examine predictors related to such deferrals among repeat blood donors. Materials and Methods: We included 385,357 donors with at least two visits to the blood centre between January 1996 and December 2006 who were not deferred due to haemato- crit at their first visit. We evaluated variables related to the development of low Hct (LHct- below 38% for females and 39% for males) after whole blood donations. Results: Over the 11-year period, 3,850 (1.5%) of the 252,301 males and 18,104 (13.6%) of the 133,056 females were deferred due to LHct at some point after their first donation. Genders, age, baseline Hct, Hct at the visit immediately before deferral due to LHct, and interval between donations, were associated with higher rates of development of LHct in repeat donors. Conclusion: Our analysis showed that deferral due to low Hct levels in repeat blood donors is highly prevalent in Brazil. Assigning longer donations intervals based on the Hct levels at the qualifying donation or supplementing iron to donors at risk may decrease deferral rate of donors with low Hct. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Whole blood donation results in the loss of approxi- mately 200–250 mg of iron for each 450 ml of blood col- lected [1–3]. Therefore, iron deficiency anaemia is a common complication of frequent blood donation espe- cially in women of childbearing age [4–8]. In the donation process, haematocrit (Hct) or haemo- globin level (Hb) are both used to anaemia determine anaemia from a blood sample obtained before donation. This is a well-established practice and its primary objective is to protect the donors health. Evaluating Hb levels is also important to avoid blood collection from donors who have a high risk of becoming anaemic. The deferral due to the risk of anaemia development requires attention. It is known that the iron stocks are highly controlled by the 1473-0502/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.transci.2013.09.009 ⇑ Corresponding author. Address: Fundação Pró-Sangue/Hemocentro de São Paulo, Av. Dr Enéas de Carvalho Aguiar, 155, 1° andar, São Paulo- SP, 05403-000, Brazil. Tel.: +55 11 30615544x336; fax: +55 11 30888317. E-mail address: sabinoec@usp.br (E.C. Sabino). Transfusion and Apheresis Science 49 (2013) 553–559 Contents lists available at ScienceDirect Transfusion and Apheresis Science journal homepage: www.elsevier.com/locate/transci