Iron Deficiency Anaemia - Draft
The following guide has been developed with the support of local gastroenterologists and is currently under review.
There are many causes of anaemia so please see the Anaemia page for advice on initial investigation and management.
This page is specifically intended for patients with true iron deficiency anaemia (or iron deficiency without anaemia)
You may also find the following CKS guidelines helpful:
True iron deficiency anamia
Initial investigation should establish if anaemia is truly due to iron deficiency.
IDA is normally suspected if the anaemia is microcytic but this is not always the case*.
Haematinics should normally be performed and ferritin is usually low in IDA. However, ferritin can be falsely raised in some conditions, so if IDA is still suspected then consider further investigations.
*It is important not to miss is an underlying iron deficiency as iron deficiency anaemia may be normocytic in some elderly patients and sometimes the ferritin is spuriously raised and so appears to be “normal”. Any inflammatory condition (such as rheumatoid disease) can falsely raise the ferritin even in the presence of iron deficiency anaemia, as can chronic kidney disease, liver disease, malignancy, hyperthyroidism and heavy alcohol intake.
To help clarify the situation, it may be worth also checking the patient’s iron status (for NBT, available on ICE as iron status under haematology panel, for UHB can request zinc protoporphyrin - ZZP). The finding of a low serum iron and/or low transferrin saturation (or raised ZPP) would point towards an iron deficiency.
Summary of investigations:
- Iron status (NBT) or Zinc protoporphyrin (UHBW) if required.
- U and E
- Coeliac screen
- Urine dip
- FIT test
Once an iron deficiency picture has been established then further investigations should be directed according to the suspected cause.
A thorough history and examination should be undertaken and if there is no obvious focus of bleeding that could explain the anaemia (e.g. menorrhagia, recurrent epistaxis) then the following should be considered:
- Lower GI causes - ask about rectal bleeding and changes in bowel habit. Examine for abdominal masses and undertake rectal examination if appropriate. Consider a FIT test.
- Upper GI causes - ask about NSAID use. Any dyspepsia or dysphagia.
- Urological causes - ask about visible haematuria and dip the urine.
If there are no symptoms and examination is normal, then investigation of IDA should initially prioritise the exclusion of lower GI causes. Investigation of upper GI and other causes can then follow if required.
If iron deficiency is associated with red flags then FIT test or 2WW referral may be indicated - see Red Flag section below.
If there are red flags and malignancy is suspected then please consider the following 2WW guidelines:
Lower GI 2WW guidlines - includes advice on when to undertake a FIT test.
If a 2WW referral is not indicated then consider referral for lower GI endoscopy initially via eRS direct to test.
If lower GI investigations are normal then consider upper GI endoscopy via eRS direct to test.
If a GI cause for iron deficiency anaemia is not apparent from initial upper and lower GI investigations or a patient is not suitable for direct to test, then please consider the following before referral:
- Medication - culprit drugs (e.g. NSAIDs, aspirin, anticoagulants, bisphosphonates) should be reviewed.
- Ensure the picture is true iron deficiency (you would be surprised how often patients are investigated in whom it isn’t true iron deficiency….)
- Dip the urine for blood - consider urological investigations if positive. See Haematuria page.
- Check the patient has had upper and lower GI endoscopy within the recent past (certainly within 12 months) and ensure that the quality of the endoscopic investigations are good (e.g. sometimes there is very poor bowel prep, incomplete colonoscopy etc) and consider repeating if concerned.
- Check coeliac serology – if positive then see Coeliac disease page.
In all patients, consider oral iron supplements which can be started prior to endoscopy (although if 2ww colonoscopy is requested it would be best to advise patient to not start taking the iron until the colonoscopy has been performed, but they can be given the prescription).
Monitor Hb and if it drops again or fails to increment adequately with oral iron then refer to secondary care for consideration of small bowel investigation.
If referral is indicated, then please refer to gastroenterology via eRS (UHBW or NBT) initially where a decision on further investigation can be made (including onward referral for capsule endoscopy if this is necessary).
If you are uncertain about appropriateness of referral, then consider requesting gastroenterology A and G.
For iron-deficient anaemia, small bowel investigation is only indicated for cases that fail to correct with iron replacement (or maybe need transfusion), or sometimes when there is recurrent IDA. This is because the pathology yield from small bowel investigation is relatively low.
Proceeding directly to small bowel investigations is only indicated when there is ongoing Melaena with normal investigations – these patients tend to be under secondary care already.
The above advice is based on BSG guidelines (1) with local guidance provided by Dr Ana Terlovich (Consultant gastroenterologist at NBT).
Oral iron supplements can be usually be started while awaiting investigation (although if 2ww colonoscopy is requested it would be best to advise patient to not start taking the iron until the colonoscopy has been performed).
In patients who do not tolerate oral iron or do not respond to oral iron supplements then an iron infusion may be considered.
Please see the Pathology page on Remedy for advice on services available at UHBW and NBT and how to refer.
Iron Deficiency without Anaemia
The British Society of Gastroenterology Guidelines on Management of IDA (2011) has advice on how to manage patients with low iron and normal Hb as well as iron deficiency anaemia - summary as below:
'Iron deficiency without anaemia is three times as common as IDA, but there is no consensus on whether these patients should be investigated, and further research is needed. The largest study shows very low prevalence of GI malignancy in patients with iron deficiency alone (0.9% of postmenopausal women and men, and 0% of premenopausal women)(2). Higher rates have been reported only in more selected groups. In the absence of firm evidence, we tentatively recommend coeliac serology in all these patients but that other investigation be reserved for those with higher-risk profiles (eg, age >50 years) after discussion of the risks and potential benefits of upper and lower GI investigation. All others should be treated empirically with oral iron replacement for 3 months and investigated if iron deficiency recurs within the next 12 months.
(2) Ioannou GN, Rockey DC, Bryson CL, et al. Iron deficiency and gastrointestinal malignancy: a population-based cohort study. Am J Med 2002;113:276e80.'