Iron status in Canadian Blood Services donors

Author: Mindy Goldman, MD, FRCPC
Online publication date: June 2014

Key points

  • Iron deficiency is common in blood donors, particularly female donors, donors donating frequently, and donors failing their hemoglobin (Hb) screen.
  • Donors are advised to speak to their physician and/or pharmacist about iron supplementation.
  • Canadian Blood Services (CBS) is performing a study on measurement of ferritin levels in randomly selected donors across Canada.

Introduction

Iron is an essential nutrient, and iron balance is precarious for much of the world’s population. In North America, iron deficiency is common in distinct population groups, such as women of child-bearing age.1 Transfusion therapy is a cornerstone of modern medical care. Canada’s need for fresh blood components, including red blood cells, is met by approximately 600,000 volunteer donors. Canadian Blood Services (CBS) collects, processes, tests, and distributes blood components to all provinces and territories, except Quebec. Each year, CBS collects approximately 950,000 units of whole blood of 500 mL each. A dedicated group of repeat donors provide close to 90% of donations, while 10% of donations come from first time donors. The average donation frequency in 2013 was slightly over 2 donations per donor yearly. Each whole blood donation results in the loss of 225 to 250 mg of iron. Donor hemoglobin (Hb) screening is performed on a fingerstick capillary sample prior to each donation, with a minimum qualifying level of 125 g/L required for both male and female donors, and 8% of female donors and 0.5% of male donors are temporarily deferred for inadequate Hb level. However, no routine measurement of serum iron stores is performed. There is increasing concern that blood donation results in iron deficiency particularly in frequent donors, and that this is under-recognized by both donors and their physicians.2-4

Symptoms of iron deficiency in blood donors

Blood donors are selected to be healthy individuals with few underlying illnesses. Iron deficiency in blood donors has clearly been shown to lead to pica (craving for unnatural food substances, such as ice) and restless leg syndrome.5 Iron deficiency without anemia has also been associated with fatigue and poor effort tolerance, although few studies have been done in otherwise healthy donors.6-9 Similarly, iron deficiency has been associated with learning and cognitive difficulties, particularly in children and adolescents.9 If iron deficiency is not treated, it may progress to iron deficiency anemia. At CBS, the Hb deferral rate (Hb below 125 g/L) is approximately 3.5% in first time female donors, compared to 10% in females who had donated 2 or more times in the past year. In male donors, the frequency of deferral for Hb is approximately 0.2% in first time donors, and 1% in males who have donated 3 or more times in the past year.

In addition to lack of knowledge about the prevalence of iron deficiency, the field is complicated by previous hypotheses regarding decreased cardiac disease risk associated with reduced iron stores, which have not been substantiated in later studies.2-4 Additionally, otherwise healthy individuals developing iron deficiency associated with blood donation may undergo extensive unnecessary investigations to determine a cause for the iron deficiency.2-4

Iron status in CBS donors

We performed a study of 550 donors who successfully donated and 50 donors deferred for low Hb to assess the prevalence of iron deficiency in CBS donors, as measured by serum ferritin levels.10 In addition, we evaluated donors’ knowledge of the impact of blood donation on their iron needs, and discussions that they may have had with their family physician about iron and blood donation. After providing donors with their ferritin results, we contacted study participants again regarding their subsequent actions, including discussions with their physicians about iron supplementation.

The main findings of the study were:

  1. Donor knowledge about iron is poor, and few donors discuss blood donation with their physician. Most donors are unaware of iron depletion as a possible adverse consequence of frequent donation. Regular physician visits are a missed opportunity to discuss blood donation and iron needs, even for donors who have failed their Hb screen and are likely to have iron deficiency anemia.
  2. Donors passing their Hb screen are often iron deficient. Table 1 summarizes the fingerstick Hb levels and ferritin levels in donors who successfully donated or were deferred for low Hb. Ferritin levels decrease substantially when comparing first time donors to repeat donors (individuals who have donated at least once in the last two years). A ferritin level below 12 μg/L indicating absent iron stores, was found in 8% of first time female donors and 23% of repeat female donors. For male donors, a ferritin level below 12ug/L was found in no first time donors, but in 9% of repeat donors.
  3. Almost all donors failing their Hb screen are iron deficient. Almost all donors deferred for low Hb were female, and 70% of deferred females had ferritin below12 μg/L (Table 1).
Table 1 Hb and ferritin levels in donors who successfully donated or were deferred for low hemoglobin (Hb)
Cohort Number of donors Mean Hb
(g/L)
Ferritin (μg/L)
  Mean <12 n(%) 12-24 n(%) >25 n(%) p-value†
Donated              
     Female 295            
          First time 84 140 37 7 (8) 27 (32) 50 (60) <0.0001
          Repeat donor 211 137* 24* 48 (23) 86 (41) 77 (36)  
 
     Male 255            
          First time 64 156 131 0 (0) 3 (5) 61 (95)  
          Repeat donor 191 152* 44* 18 (9) 62 (32) 111 (58) <0.0001
 
Deferred              
     Female 47 117 11 33 (70) 9 (19) 5 (11) NS
     Male 3 118 17 1 (33) 1 (33) 1 (33)  

*p<0.05
†p-value comparing slope of trend line between groups

  1. Donors with low ferritin who see their physician are not always advised to take iron supplements. Of the 98 donors who saw their physician, 50% had been started on iron supplementation, while 10% had started multivitamins containing some iron, and 21% had been told to stop donating blood. These donors require iron supplementation, rather than changes to diet or multivitamins with iron to rebuilt their iron stores, particularly if they would like to continue to donate blood.3,4,11-14 Results in our donors are similar to those seen in studies of US, Australian and US blood donors.2-4,11-15

Operational study of iron deficiency

CBS will begin an operational study measuring ferritin levels in 10,000 to 15,000 donors who successfully donate over the next year. Donor clinics across Canada will be randomly selected to have ferritin levels tested. Donors with low ferritin will receive a letter and an information sheet, advising them to see their physician and/or pharmacist about starting iron supplements (Figure 1). Donors should wait a minimum of 6 months before returning to donate, and have their ferritin level rechecked before returning to donate.

Recommendations

Donors failing their hemoglobin screen

Almost all donors failing their Hb screen (Hb below 125 g/L) have low or absent iron stores. These individuals are given an information sheet, advising them to see their physician for investigation (Figure 2). Investigations may include a repeat of the Hb measurement on a venous sample, as part of a complete blood count done on a laboratory analyzer. This test is more accurate than the fingerstick Hb performed on a portable hemoglobinometer in donor clinics. Additionally, these donors may have their ferritin measured. Other investigations may be appropriate, depending on a variety of factors. These include the presence of iron deficiency alone or iron deficiency anemia, the patient’s age and gender, menstrual status, family history of gastrointestinal cancer, and the presence of any symptoms or signs of possible underlying conditions. Guidelines developed by the British Society of Gastroenterology recommend obtaining a history of blood donation as part of the investigation of iron deficiency.16 Clearly, a trial of iron supplementation, temporary cessation of blood donation, and repeat evaluation after six months may be appropriate in a young female frequent blood donor, while a gastrointestinal investigation may be indicated in a first time older male donor. On the information sheet (Figure 1), donors are advised not to return to donate until they have seen their physician, and the cause of the anemia has been determined. If donors are placed on iron supplementation for iron deficiency anemia, they are advised not to return to donate until they have completed 6 months of therapy and the iron deficiency anemia has resolved.

Donors who are successfully donating

Since iron deficiency is so common in regular blood donors, we recommend that donors and physicians discuss blood donations on regular check-up visits. Individuals with possible symptoms of iron deficiency, such as pica, restless leg syndrome, and unexplained fatigue should have ferritin levels measured. Additionally, other individuals who are donating frequently, particularly females donating at least twice a year and males donating 3 or more times a year have a high likelihood of iron deficiency and should have ferritin levels measured. Studies have shown that supplementation of from 2000 to 4000 mg of elemental iron as a total dose will replace the iron lost in a blood donation.4,14 For individuals donating on a regular basis, it is very difficult to replace the amount of iron lost in donation by diet alone or by multivitamins that contain a small amount of iron.11 Table 2 shows some iron preparations available in Canada, the elemental iron content per tablet and the number of tablets necessary to replace the iron lost in the blood donation. In most studies of iron supplementation in blood donors, donors have been advised to take one tablet daily at bedtime, preferably on an empty stomach for a one to three month period to replace iron loss. Individuals with a low ferritin clearly will require a longer period of iron supplementation to replenish their reserves. As shown in our study, many female donors already have low iron reserves before starting to donate blood. Individuals taking iron supplements who have been diagnosed with iron deficiency without anemia are advised to resume donation after their iron stores have been shown to have returned to normal.

Table 2 Iron supplementation necessary to replace one whole blood donation
Iron Preparation Tablet (mg) % of elemental iron Elemental iron content per tablet # tablets, 2000 mg total dose # tablets 4000 mg total dose
Ferrous sulfate 300 mg 20% 60 mg 33 66
Ferrous gluconate 300 mg 11.6% 35 mg 57 114
Ferrous fumarate 300 mg 33% 99 mg 20 40
Polysaccharide-iron complex 150 mg 100% 150 mg 14 28

Conclusion

Approximately 600,000 people, or 2% of the Canadian adult population, enable lifesaving treatments for their fellow citizens by donating blood. Iron deficiency is a common problem in the Canadian population, particularly in women of child-bearing age. Blood donation has a significant impact on iron stores in frequent donors, particularly females. Several measures are necessary to prevent, detect, and treat iron deficiency in donors. These include less frequent donation by donors most susceptible to iron deficiency, and better education of both donors and their physicians about iron needs associated with blood donation. Frequent donors are encouraged to discuss blood donation and possible need for ferritin monitoring and iron supplementation with their physicians. Conversely, when assessing iron deficiency or nonspecific symptoms such as fatigue, physicians should ask their patients about blood donation. Regular blood donors may require a course of iron supplements to replenish the iron lost in blood donation. These individuals can often return to blood donation, after an adequate course of iron supplementation.

Figure 1

Donor Information Sheet- donors passing hemoglobin screen with low ferritin results

What happens during a blood donation?

Red blood cells are red because of the way iron is carried in hemoglobin, a protein that carries oxygen. Removing red blood cells in blood donation also removes iron. To make new red blood cells, you use iron already stored in your body, or iron in the food that you eat or in supplements that you take.

Does Canadian Blood Services test all donors for low iron?

Canadian Blood Services does a fingerstick test on all donors to measure hemoglobin level. However, donors can have normal hemoglobin, but low iron stores. Canadian Blood Services has just started measuring iron stores (ferritin) on some donor clinics.

Why do I have low iron stores (low ferritin)?

Causes of low ferritin include frequent blood donation (especially more than twice a year), low iron in your diet, menstrual blood loss in women, and more rarely, gradual bleeding in the digestive tract, such as stomach or colon.

How may low iron stores affect my health?

Low iron stores can lead to fatigue and poorer exercise capacity. Some people have a craving for ice. If iron levels drop more, your hemoglobin could drop and this may have a greater impact on your energy level.

What should I do now?

We recommend that you see your doctor. He or she can check if you need any other tests done, and advise you about iron supplements. A diet rich in iron is recommended for all blood donors. However, since your ferritin level is low, iron supplements would be helpful to build up your iron stores.

Can I go to my pharmacist and get iron over the counter?

You don’t need a prescription to get iron supplements.

You can talk to your pharmacist about starting over the counter iron supplements.

We recommend that you speak to your doctor first if :

  • you have any gastrointestinal illness or symptoms, such as stomach ulcers, chronic constipation or diarrhea, intestinal polyps
  • you are taking aspirin or anti-inflammatory pills (such as Advil or Ibuprofen) regularly
  • you have family members with a history of colon cancer or polyps

You should not take iron supplements if you have been diagnosed with hemochromatosis (iron overload) in the past.

Can I continue to donate blood?

Most people are able to improve their iron stores and return to donate.

We recommend that you wait a minimum of 6 months from your last donation before donating whole blood again. Please call us to cancel any appointments that you have already booked in the next 6 months. We apologise if you are called to donate sooner. Your doctor should check that your ferritin level is back to normal before you return to donate blood. Usually at least 3 months of iron supplements will be needed to return your iron stores to normal.

Where can I get more information?

You can visit our website, www.blood.ca, under “Can I donate”, Basic Eligibility, Hemoglobin and Iron.

Our educational website blood.ca/professionaleducation contains more technical information for your doctor.

You can call 1-888-2DONATE for questions about your eligibility to donate. You may be referred to the Canadian Blood Services medical office nearest you.

Since this is a new activity for us, we will be sending you a short e mail survey, if we have your e mail address, to help us improve our service to donors. Your participation is entirely voluntary and confidential will not become part of your blood donor record.

References

  1. Cooper M, Greene-Finestone L, Lowell H, Levesque J, Robinson S. Iron sufficiency ofCanadians. Health Rep 2012; 23(4):41-48.
  2. Popovsky MA. Anemia, iron depletion, and the blood donor: it’s time to work on the donor’sbehalf. Transfusion 2012; 52:688-692.
  3. Brittenham GM. Iron deficiency in whole blood donors. Transfusion 2011; 51:458-461.
  4. AABB Association Bulletin #12-03 -Strategies to Monitor, Limit, or Prevent Iron Deficiency in Blood Donors. URL: http://www.aabb.org/resources/publications/bulletins/Pages/ab12-03.aspx
  5. Bryant BJ, Yau YY, Arceo SM, Hopkins JA, Leitman SF. Ascertainment of iron deficiencyand depletion in blood donors through screening questions for pica and restless leg syndrome.Transfusion 2013; Jan 10.doi:10.1111/trf/12061 (Epub ahead of print).
  6. Vaucher P, Druais P-L, Waldvogel S, Favrat B. Effect of iron supplementation on fatigue innonanemic menstruating women with low ferritin: a randomized controlled trial. Can MedAssoc J 2012; 184:1247-1254.
  7. Verdon F, Burnand B, Fallab Stubi C-L, Bonard C, et al. Iron supplementation forunexplained fatigue in non-anaemic women: a double blind randomised placebo controlledtrial. BMJ 2003; 326:1124-1127.
  8. Waldvogel S, Pedrazzini B, Vaucher P, Bize R, et al. Clinical evaluation of iron treatmentefficiency among non-anemic but iron deficient female blood donors: a randomizedcontrolled trial. BMC Medicine 2012; 10:8.
  9. Falkingham M, Abdelhamid A, Curtis P, Fairweather-Tait S, et al. The effects of oral ironsupplementation on cognition in older children and adults: a systematic review and meta-analysis. Nutrition Journal 2010; 9:4.
  10. Goldman M, Uzicanin S, Scalia V, et al. Iron deficiency in Canadian blood donors.Transfusion 2014; 54:775-779.
  11. Booth AO, Lim K, Capper H, et al. Iron status and dietary iron intake of female blooddonors. Transfusion 2014; 54-770-774.
  12. Gorlin J. Iron man pentathlon or “we have met the enemy and they is us!” Transfusion 11 2014; 54:747-749.
  13. O’Meara A, Infanti L, Stebler C, Ruesch M, et al. The value of routine ferritin measurement in blood donors. Transfusion 2011; 51:2183-2188.
  14. Bryant BJ, Yau YY, Arceo SM, Daniel-Johnson J, et al. Iron replacement therapy in the routine management of blood donors. Transfusion 2012; 52:1566-1575.
  15. Cable RG, Glynn SA, Kiss JE, Mast AE et al. Iron deficiency in blood donors: analysis of enrollment data from the REDS-II Donor Iron Status Evaluation (RISE) study. Transfusion 2011; 51:511-522.
  16. Goddard AF, James MW, McIntyre AS, Scott BB. Guidelines for the management of iron deficiency anaemia. Gut 2011; 60:1309-1316.