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Question answered:23/06/06 Warning! this question is over two years old.

We identified two British guidelines on iron deficiency anaemia (IAD) which both employ haemoglobin levels as one indicator for IAD.

The PRODIGY guideline on iron deficiency anaemia details investigations useful in the diagnosis of anaemia:

“Full blood count:
• Low haemoglobin (Hb) concentration, less than 13 g/dl for men and less than 12 g/dl for women
• Low MCV, MCH, and MCHC (mean cell volume, mean cell Hb, mean cell Hb concentration)
• Reticulocyte count low for the degree of anaemia
• There may be a mild thrombocytosis (raised platelet concentration)
• Serum ferritin level: low (an indicator of reduced body-iron stores). However, as ferritin is an acute-phase protein, levels may be normal or elevated in infective, inflammatory or malignant disease despite iron deficiency. Serum ferritin level is also increased by excessive alcohol consumption.

The clinical scenario “Iron deficiency anaemia excluding pregnancy” notes:

• A reason for iron deficiency should always be sought.
• Consider gastrointestinal blood loss, excessive menstrual loss, malabsorption, or nutritional deficiency.
• Dietary deficiency, by itself, is rarely a cause of iron deficiency anaemia in developed countries unless there are increased physiological demands for iron (e.g. during adolescence, pregnancy, lactation, and in menstruating women).
• Give oral iron (e.g. ferrous sulphate 200 mg three times a day) to anyone with iron deficiency anaemia. Continue treatment for 3 months once the haemoglobin has normalized.” [1]

The British Society of Gastroenterology issued a guideline on the management of iron deficiency anaemia (IDA) in May 2005 in which it distinguishes between anaemia and iron deficiency:

“The WHO defines anaemia as a haemoglobin below 13 g/dL in men over 15 years, below 12 g/dL in non-pregnant women over 15 years, and below 11 g/dL in pregnant women. The diagnostic criteria for anaemia in IDA vary between published studies. The normal range for haemoglobin also varies between different populations in the UK. Therefore, it is reasonable to use the lower limit of the normal range for the laboratory performing the test to define anaemia."

It adds that, “There is little consensus as to the level of anaemia that requires investigation”.

“… The serum markers of iron deficiency are low ferritin, low iron, raised total iron binding capacity, raised red cell protoporhyrin and increased transferrin binding receptors (sTfR). Serum ferritin is the most powerful test for iron deficiency (A). The cut-off level of ferritin which is diagnostic varies between 12–15 ìmg/L (12,16,17). This value only holds for patients without co-existent disease. In such settings, a cut-off value of <50 ìmg/L is still consistent with iron deficiency…”

Concerning the management of IDA

“Iron therapy
Treatment of an underlying cause should prevent further iron loss but all patients should have iron supplementation both to correct anaemia and replenish body stores (B). This is achieved most
simply and cheaply with ferrous sulphate 200 mg twice daily. Lower doses may be as effective and better tolerated and could be considered in patients not tolerating traditional doses. Other iron compounds (e.g. ferrous fumarate, ferrous gluconate) or formulations (iron suspensions) may also be tolerated better then ferrous sulphate. Ascorbic acid (250–500 mg twice daily with the iron preparation) may enhance iron absorption. We recommend that oral iron is continued until three months after the iron deficiency has been corrected so that stores are replenished.” [2]

The BSG guideline also briefly considers iron deficiency without anaemia but does not make any recommendations regarding its management:

“Iron deficiency without anaemia (as proven by a low serum ferritin – hypoferritinaemia) is three times as common as IDA55, but there is little consensus on whether these patients should be investigated.”

An article published in the BMJ however does examine the effect of iron supplementation for unexplained fatigue in 144 non-anaemic women most of whom had low serum ferritin levels:

“Results 136 (94%) women completed the study. Most had a low serum ferritin concentration;  20 µg/l in 69 (51%) women. Mean age, haemoglobin concentration, serum ferritin concentration, level of fatigue, depression, and anxiety were similar in both groups at baseline. Both groups were also similar for compliance and dropout rates. The level of fatigue after one month decreased by -1.82/6.37 points (29%) in the iron group compared with -0.85/6.46 points (13%) in the placebo group (difference 0.95 points, 95% confidence interval 0.32 to 1.62; P=0.004). Subgroups analysis showed that only women with ferritin concentrations  50 µg/l improved with oral supplementation.
Conclusion Non-anaemic women with unexplained fatigue may benefit from iron supplementation. The effect may be restricted to women with low or borderline serum ferritin concentrations. “ [3]

References
1. British Society of Gastroenterology. Guidelines for the management of iron deficiency anaemia. May 2005. (http://www.bsg.org.uk/pdf_word_docs/iron_def.pdf).
2. PRODIGY guideline on iron deficiency anaemia. Last revised July 2005. (http://www.prodigy.nhs.uk/anaemia_iron_deficiency/).
3. Verdon F, Burnand B and Stubi C et al. Iron supplementation for unexplained fatigue in non-anaemic women: double blind randomised placebo controlled trial. BMJ  2003;326:1124 (24 May), doi:10.1136/bmj.326.7399.1124. (http://bmj.bmjjournals.com/cgi/content/full/326/7399/1124).

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