Vox Sanguinis (2013) 104, 110–114 ª 2012 The Author(s) Vox Sanguinis ª 2012 International Society of Blood Transfusion DOI: 10.1111/j.1423-0410.2012.01644.x
ORIGINAL PAPER
Characterization of blood donors with high haemoglobin concentration K. Magnussen,1 H. C. Hasselbalch,2 H. Ullum1 & O. W. Bjerrum3 1
Department of Clinical Immunology and Blood Centre, Rigshospitalet ⁄ Hvidovre Hospital, University Hospital of Copenhagen, Copenhagen, Denmark Department of Haematology, Roskilde Hospital, University Hospital of Copenhagen, Denmark 3 Department of Haematology, Rigshospitalet, University Hospital of Copenhagen, Denmark 2
Background and Objectives The literature contains little on the prevalence and causes of high predonation haemoglobin levels among blood donors. This study aimed to characterize and develop an algorithm to manage would-be donors with polycythaemia. Materials and Methods Between November 2009 and November 2011, we offered haematology consultations to blood donors with repeated haemoglobin concentration (Hb) above the WHO limit for polycythaemia vera (PV) (10Æ2 and 11Æ5 mM ⁄ 16Æ5 and 18Æ5 g ⁄ dl for women and men, respectively). Investigation of such donors included Hb, haematocrit, mean cell volume, erythropoietin, ferritin, platelet count and leucocyte count, JAK2 V617 and JAK2 exon12 analysis, as well as other routine measurements. Results Among 46 such donors, 39 had a history of smoking, which contributes to erythrocytosis. Two had PV, five had severe hypertension, one of them because of renal artery stenosis, and two had diabetes mellitus. Thus, we found a high morbidity among such donors. Of the 36 others, 30 donated again before May 2012, at which time the Hb was significantly lower.
Received 24 May 2012, revised 13 July 2012, accepted 16 July 2012, published online 15 August 2012
Conclusion We recommend JAK2 V617 and JAK2 exon12 screening and clinical investigation for donors with concurrently high Hb, high haematocrit and iron deficiency. We also recommend that they stop or cut down on smoking to reduce the risk of thrombosis in general. We disqualified 10 of the donors. Key words: donors, Haemoglobin, polycythaemia, donor vigilance, red cell components, transfusion medicine (in general).
Introduction The literature contains little on the prevalence and causes of abnormally high haemoglobin levels in blood donors. In the year before this project, we encountered two donors with elevated Hb and diagnosed polycythaemia vera (PV) in them. Therefore, we sought data to support a rational clinical algorithm to manage high-Hb donors.
Correspondence: Karin Magnussen, MD, Department of Clinical Immunology and Blood Centre, Hvidovre Hospital, Kettegaard Alle, 2650 Hvidovre, Denmark E-mail:
[email protected]
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An excess of red blood cells, erythrocytosis, may be primary (PV), or secondary, caused by either congenital or acquired factors [1]. An elevated Hb or haematocrit (Hct) is often the observation indicating PV, and each individual blood donor is screened by at least one of these at each visit in the blood bank. A few studies before the JAK2 era [2–5] and after 2005 [6] reported on PV in blood donors. Some such patients seemed to show an association with blood donation [2–4, 6], perhaps acquiring the disorder from erythropoiesis stimulated by phlebotomy. The donor populations have varied in other studies. Besides, revised diagnostic criteria for PV are now based on WHO 2008, including the JAK2 status as a major criterion [7].
High haemoglobin blood donors 111
Materials and methods The Capital Region of Denmark collects about 110 000 blood donations per year. All donors, who are voluntary and unpaid, fill in a health questionnaire and have an interview before donation. With every donation, Hb is measured in venous blood from a presample bag attached to the blood bag (CPD ⁄ SAG-M QUAD Optipure RC Fenwal). For inclusion in this study, the upper limit was chosen according to WHO recommendations for PV [7], that is, women with Hb above 10Æ2 mM (16Æ5 g ⁄ dl) and men above 11Æ5 mM (18Æ5 g ⁄ dl) on two succeeding donations. All Hb were recorded in our donor IT-system. Immediately after the second high-Hb test, all such persons were offered clinical investigations by a hospital-based consultant in haematology. They were informed by telephone and letter, with assurance that participation was voluntary. Following consultation, blood samples were drawn for testing at laboratories approved by Danish standards and using only validated methods. Testing included Hb, Hct, mean cellular volume (MCV), erythropoietin (EPO), ferritin, transferrin and iron, leucocyte count, platelet count, JAK2 V617F [8] and JAK2 exon12 mutations [9]. Most donors were also screened for glucose, creatinine, thyroid-stimulating hormone, liver enzymes, etc. The total red cell mass was measured in a few donors. Selected donors had haemoglobin electrophoresis or endogenous erythroid colony assays. Vital parameters like blood pressure, pulse, oxygen saturation and clinical examination were routine. In the Copenhagen Capital Region, we have a stable cohort of approximately 55 000 blood donors, including 12 000 new donors every year.
2012, apart from those already investigated. In all, from 224 357 donations, we offered further investigation to 48 donors (0Æ021%, 35 women and 13 men). Only two declined, one because of concurrent investigations for diabetes mellitus, and the other because of a self-motivated reduction in smoking and coffee, which reduced her Hb from 10Æ3 mM (16Æ6 g ⁄ dl) to 9Æ5 mM (15Æ3 g ⁄ dl) at her next donation 6 months later. Accordingly, we included 46 donors in the study (33 women and 13 men) in addition to the two male donors diagnosed with PV in the year preceding this study. We included the latter two so as to illustrate in more detail the profile of patients with PV in this population of blood donors.
Polycythaemia vera Of the 46 high-Hb donors, one had JAK2 V617F positive PV. He was 59 years old and had donated 99 times. His Hb was 11Æ6 mM (18Æ7 g ⁄ dl) with a mutation load of 37%. His Hb had been stable at approximately 10Æ0 mM (16Æ1 g ⁄ dl) and then increased over five donations to reach 11Æ4 mM (18Æ4 g ⁄ dl) four donations before inclusion. A 66-year-old man with Hb of 11Æ8 mM (19Æ0 g ⁄ dl) was JAK2 negative for both V617F and exon12, but positive in the endogenous erythroid colony assay and was diagnosed with PV. He had donated 103 times at the time of diagnosis. His Hb had been above 11Æ5 mM (18Æ5 g ⁄ dl) since 2005 and before that approximately 11 mM (17Æ7 g ⁄ dl). Of the two donors found in the preceding year to have PV, one was JAK2 V617F positive and one was JAK2 exon 12 positive. They had both donated 10 to 12 times with Hb above 11 mM (17Æ6 g ⁄ dl) and before that had between 10Æ0 and 10Æ5 mM (16Æ1–16Æ9 g ⁄ dl).
Statistics We used Student’s t-test with a significance level of 5% for statistical analysis. The computer program Excel (Microsoft) was used for the calculations. Data are presented as means with range.
Results The study period was 2 years from 11 November 2009 to 27 November 2011. We included the preceding year’s two donors diagnosed with PV. Except for the Hb, the laboratory values were obtained at the first clinical examination, usually within 1 month of the donation; hence, Hct and ferritin may be lower than before the donation and EPO may be higher. During the first year, of 117 477 donations, there were 118 with high Hb and 33 of them had two high values in a row (0Æ028%). In the second year, with 106 880 donations, Hb was high in 126 of whom 15 donors were repeatedly high (0Æ014%). Interestingly, we found no repeatedly high Hb results between October 2011 and May 2012 The Author(s) Vox Sanguinis 2012 International Society of Blood Transfusion Vox Sanguinis (2013) 104, 110–114
Hypertension Five donors (11%; four women, one man) were found to have severe hypertension with a systolic pressure 180– 230 mmHg and diastolic 100–146 mmHg, respectively, but not confirmed to have PV. One of the women with hypertension had concomitant diabetes mellitus, and another hypertensive woman was diagnosed and treated for renal artery stenosis.
Diabetes mellitus Two women were diagnosed with diabetes mellitus, one with concomitant myxoedema and the other with hypertension as mentioned above.
Normal variation One male donor was JAK2 wild type, and no secondary cause of erythrocytosis was found. This man had normal
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blood tests, including endogenous erythroid colony assay, and we concluded that the high Hb [12Æ0 mM (19Æ3 g ⁄ dl)] was a normal variation, and he has now returned as a regular blood donor.
Other deferred donors One woman with secondary erythrocytosis was excluded before the next donation because of an unspecified medication. One male donor dropped out after the initial investigations, which had revealed moderate hypertension and high homocysteine and cholesterol levels.
Smoking About 85% of the high-Hb donors were smokers, including one of those diagnosed with PV. One male donor 36 years of age from Pakistan with Hb 11Æ6 mM (18Æ5 g ⁄ dl) and noniron-deficient microcythaemia (MCV 79fl) was tested with haemoglobin electrophoresis, which was normal. Smoking probably caused his high Hb, but we found no explanation Table 1 Basic data on the blood donors included
Age Mean (range) Number of donations Mean (range) Plethoric N Hypermetabolic symptoms N Smokers N B-Hb mM Mean (range) B-Hb g ⁄ dl Mean (range) B-Hct % Mean (range) P-EPO IU Mean (range) E-MCV fl Mean (range) P-Ferritin lg ⁄ l Geomean (range) B-Leucocyte count 109 ⁄ l Mean (range) B-Platelet count 109 ⁄ l Mean (range)
Men with PV
Men no PV
Women no PV
61 (55–66) N=4 115 (80–176) N=4
51 (29–66) N = 11 69 (7–134) N = 11
52 (27–64) N = 33 42 (2–100) N = 33
4 (100%) N=4 2 (50%) N=4 1 (25%) N=4 12Æ0 (11Æ6–12Æ6) N=4 19Æ3 (18Æ7–20Æ3) N=4 54 (51–57) N=4 3Æ4 (2Æ1–5Æ8) N=3 79 (74–89) N=4 19 (9–36) N=4
6 (55%) N = 10 1 (9%) N = 10 9 (82%) N = 11 11Æ9 (11Æ6–12Æ4) N = 11 19Æ2 (18Æ7–20Æ0) N = 11 51 (47–53) N = 10 8Æ8 (5Æ7–15Æ4) N=9 92 (79–99) N = 10 91 (36–194) N = 11
5 (15%) N = 30 0 N = 30 29 (88%) N = 33 10Æ7 (10Æ3–11Æ5) N = 33 17Æ2 (16Æ6–18Æ5) N = 33 46 (42–52) N = 29 9Æ4 (2Æ6–19Æ4) N = 26 92 (84–99) N = 28 37 (15–493) N = 31
11Æ4 (6Æ5–21Æ0) N=4
8Æ6 (5Æ2–13Æ1) N = 10
8Æ8 (4Æ2–16Æ3) N = 30
280 (199–400) N=4
223 (147–282) N = 10
280 (177–449) N = 29
for his microcythaemia. In all, the clinical investigations identified 10 donors (21Æ7%) who were permanently deferred from blood donation, while 33 (71Æ7%) continued as regular donors and three (6Æ5%) chose not to donate again. In Table 1, data on the included donors are presented together with data on the two donors previously diagnosed with PV. Of the four donors with PV, two are JAK2 V617F positive, one is JAK2 exon 12 positive and one has no known JAK2 mutation. There is no significant difference in Hb between the two groups of men (P = 0Æ82). The Hct in men with PV was significantly higher than in the high Hb men without PV (P = 0Æ037). EPO was only measured in three of the PV donors and in 35 of the non-PV donors, still the difference was significant (P = 0Æ022). Ferritin was significantly lower in the men with PV compared with the men without PV (P = 0Æ008). The MCV was significantly lower in men with PV compared with donors without PV (P < 0Æ000). There was no significant difference in leucocyte or platelet count between this heterogeneous group of donors diagnosed with PV and the donors without PV. Of the 36 donors not deferred after the clinical investigation, 30 donated again. Table 2 shows that the Hb at the most recent donation was significantly lower than before the clinical investigation (P < 0Æ000). This could be regression to the mean, but although we did not routinely ask the donors about changes in lifestyle, some told us they stopped or reduced smoking and consumption of coffee and tea. We therefore suggest that the reduction in Hb is indeed significant.
Discussion Measurement of either Hb or Hct is mandatory with every blood donation. Although there is a precise lower limit for donation, the upper limit is less so. According to The European Guidelines, abnormally high and low Hb should be further investigated [10]. We see far fewer high Hb values in blood donors than low, and our previous conclusion was that most of the high-Hb donors were healthy and able to donate. But we had found two male donors who were positive for JAK2 V617F and JAK2 exon 12, respectively. This and the need for an algorithm for donors with high Hb led us to investigate those with repeated high Hb level according to the WHO criteria [7], not only using JAK2 V617F and JAK2 exon 12 tests, but also a thorough clinical examination. This allows donors in need to receive treatment, while the healthy ones can continue as regular blood donors to the benefit of patients in need of blood products. Known causes of increased Hb level are PV and secondary polycythaemia because of such causes as low oxygen, lung disease, smoking, renal artery stenosis, increased secretion of EPO, hypertension, diabetes mellitus and the dehydration 2012 The Author(s) Vox Sanguinis 2012 International Society of Blood Transfusion Vox Sanguinis (2013) 104, 110–114
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Table 2 B-Hb on the donors who have donated again Donors donating again Male donors Female donors
7 23
B-Hb when included mean (range)
B-Hb at recent donation mean (range)
11Æ9 mM (11Æ6–12Æ3) 19Æ2 g ⁄ dl (18Æ7–19Æ8) 10Æ6 mM (10Æ3–11Æ5) 17Æ1 g ⁄ dl (16Æ6–18Æ5)
11Æ4 mM (10Æ9–12Æ0) 18Æ4 g ⁄ dl (17Æ6–19Æ3) 10Æ1 mM (8Æ9–10Æ8) 16Æ3 g ⁄ dl (14Æ3–17Æ4)
related to excessive intake of coffee, tea or alcohol as well as inadequate liquid intake. Healthy donors with a high Hb are desirable for the high yield of red cells. High Hb values [above 10Æ2 mM (16Æ5 g ⁄ dl) in women and >11Æ5 mM (18Æ5 g ⁄ dl) in men] are not uncommon in the general population, usually related to smoking or chronic lung disease. PV itself is a rare cause of elevated Hb [1, 11]. Haemochromatosis is not a cause of high Hb but would lead to faster progress of PV, because erythropoiesis would not be iron restricted. In fact, iron deficiency is typical for PV because of the increased erythropoiesis. Polycythaemia vera requires permanent disqualification from blood donation. The patient has to receive urgent treatment to prevent serious devastating, thrombotic complications or hypermetabolic symptoms and microcirculatory disturbances, for example, erythromelalgia owing to hyperviscosity. However, measurement of Hb in venous blood is not a reliable marker for primary or secondary erythrocytosis [12, 13], whereas the Hct reflects blood viscosity more accurately [14]. Screening blood donors may now be simpler using the molecular markers [9] analysed on blood samples [1, 7, 8]. However, these analyses are expensive and not universally available and would not have found the donor that was only positive in the endogenous erythroid colony assay. This study therefore also aimed at describing if possible, simple tests to further identify blood donors with PV. In a group of patients with myeloproliferative neoplasms, Randi et al. [4] found 18% were or had been blood donors. If a blood donor acquires undiagnosed PV, blood donation may relieve some of the symptoms, and he or she will continue to donate, perhaps even more often. But none of the donors we diagnosed reported that (data not shown). Still, regular donations may prolong the time to diagnosis, which can be risky. For example, it could be dangerous when such a person stops donating for any reason and the risk of thrombosis increases. Polycythaemia vera is a rare disease, with epidemiologic data indicating an incidence of 2Æ8 ⁄ 105 population in southern Sweden [15], and a prevalence of 0Æ2% positive for JAK2 V617F in the Copenhagen City Heart Study among 10 507 participants aged 20–95 [16]. In the present study, only approximately 0Æ02% of donations had Hb 2012 The Author(s) Vox Sanguinis 2012 International Society of Blood Transfusion Vox Sanguinis (2013) 104, 110–114
Significance P = 0Æ008 P < 0Æ000
above the WHO recommended level for investigating PV [7]. In 3 years, we found four donors with PV, of whom only two were JAK2 V617F positive, which does not suggest increased incidence in the donor population. Over time we observed a decline in the frequency of donations where Hb was repeatedly high; in fact, no additional donors with a high Hb were seen from October 2011 to May 2012. The donors who were clinically studied for repeatedly high Hb later had a significantly lower Hb level. Only three had the same or a slightly higher Hb after investigation. We suggest that the increased awareness created by a professional attitude towards these donors made at least some of them reevaluate life-style habits, such as smoking. Although an increased prevalence of PV exists in cigarette smokers [17], plethoric, non-smoking persons may be suspected of having PV although these are not reliable characteristics. Still, a nonsmoker with a high Hb is an important observation. Some recommend that JAK2 analysis be available in transfusion centres with access to molecular genetic analysis [6]. Based on this study, we recommend JAK2 V617F and JAK2 exon12 analysis for iron-depleted donors suspected to have PV [7]. However, we do not recommend routine mutation analysis, because iron status plus high Hb and Hct are sufficient to identify those with a myeloproliferative neoplasm. We regularly monitor iron status in all our donors, following a standard protocol that was developed from a previous study [18]. Arterial hypertension may accompany erythrocytosis [11], and we identified five donors in this study with severe hypertension. Early identification of potential donors with arterial hypertension is advisable. Some 18% of our donor population are smokers (H. Ullum unpublished results from the Danish Blood Donor Study), while 85% of those with high-Hb smoked. Smoking thus causes erythrocytosis, and dehydration aggravates it. In addition, hyperglycaemia was a contributing factor in two patients with type II diabetes mellitus. This patient group has a high prevalence of comorbidities (22%), and with increased hct, the risk of thromboembolic disease increases [11, 19]. In a few donors, we could not find a cause for secondary erythrocytosis [1]. We did endogenous erythroid colony assays in two [7], and haemoglobin electrophoresis [1] in another, to look for
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high-oxygen haemoglobin variants [20]. These specific tests may help in otherwise unexplained erythrocytosis. We did not do EPO-receptor or prolyl hydroxylase domain protein 2 (PHD2) gene mutation analysis to look for rare causes of secondary erythrocytosis [1, 21] in healthy donors. In summary, PV is not more frequent among regular blood donors than in the general population. We recommend measuring blood pressure, iron-profile and possibly blood glucose in donors with repeatedly elevated Hb.
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Acknowledgements Dr Morten Krogh-Jensen, Dept Hematology, Herlev Hospital, University of Copenhagen contributed data on four patients in this study. K. Magnussen, O.W. Bjerrum, and C. Hasselbalch designed and carried out the research, analysed data and wrote the paper. H. Ullum designed the research.
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2012 The Author(s) Vox Sanguinis 2012 International Society of Blood Transfusion Vox Sanguinis (2013) 104, 110–114
