๐Ÿ’‰ Anaemia (Low Hb)

RCGP SCA Algorithm โ€” UK Primary Care

NICE NG12NICE NG203NICE NG23910-min consult
๐Ÿ’‰
Anaemia (Low Hb) โ€” Investigation & Management UK primary care algorithm for adults presenting with low Hb or suspected anaemia ยท NICE NG12 / NG203 / NG239 / BSG-aligned
Progress 0 / 9

โšก Snapshot. The whole pathway on one page: act now, triage, classify, treat today and safety-net. The Steps tab holds the detail.

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1
Safety

Exclude emergencies โ€” haemodynamic compromise & can't-miss causes

Screen every patient for the following before proceeding. If any present โ†’ act immediately.
Emergency assessment Collapse, shock, ongoing major haemorrhage, severe symptomatic anaemia, myocardial ischaemia, severe hypoxia or altered consciousness โ€” interpret tachycardia and hypotension with age, baseline observations, sepsis, bleeding, medication and comorbidity โ†’ 999
Active / massive GI bleed Haematemesis, melaena, PR haematochezia with haemodynamic compromise โ†’ 999
Acute chest pain + anaemia Acute chest pain with ECG changes โ€” manage as possible ACS irrespective of the Hb; do not assume anaemia is the primary diagnosis โ†’ 999
Hb <70 g/L with significant symptoms Dyspnoea at rest, syncope, angina, heart failure, confusion, haemodynamic compromise or suspected ongoing bleeding โ†’ same-day hospital assessment; consider emergency transfer according to clinical condition and local transfusion/acute medicine protocol Same-day Transfusion is guided by symptoms, cardiovascular status, bleeding and local guidance โ€” not Hb alone.
Suspected haematological malignancy Pancytopenia, lymphadenopathy, splenomegaly, night sweats, weight loss โ†’ Very urgent FBC + film ยท NICE NG12 same-day haematology advice if it suggests leukaemia; unexplained lymphadenopathy or splenomegaly โ†’ consider a suspected cancer pathway referral for lymphoma
Unintentional weight loss + anaemia Unexplained weight loss โ€” consider GI, lung, haematological malignancy โ†’ NICE NG12 route for the likely site
Rectal bleeding + iron-deficiency Iron-deficiency anaemia at any age, or rectal bleeding (under 50 with abdominal pain or weight loss; any at 50+) โ†’ FIT; FIT โ‰ฅ10 ยตg Hb/g โ†’ Colorectal suspected cancer pathway referral FIT is a triage test, not an exclusion test; rectal mass, anal mass or anal ulceration โ†’ consider a suspected cancer referral without waiting for FIT (NG12).
Postpartum anaemia Ongoing postpartum haemorrhage or haemodynamic instability โ†’ 999 Otherwise urgency depends on bleeding, symptoms, haemodynamics, timing, comorbidity and Hb trend โ†’ Same-day obstetric if concerned
Pancytopenia Not synonymous with aplastic anaemia or malignancy, but needs urgent assessment โ€” same-day haematology with blasts or a suspicious film, severe neutropenia, severe thrombocytopenia or bleeding, rapidly falling counts, fever or sepsis, symptomatic anaemia, splenomegaly or constitutional symptoms โ†’ Same-day haematology
Haemolytic features Jaundice with falling Hb needs urgent assessment; same-day for a rapid Hb fall, severe haemolysis, haemoglobinuria, renal impairment, thrombocytopenia, neurological features or haemodynamic compromise โ†’ Same-day
Neurological B12 symptoms Paraesthesiae, unsteady gait, cognitive change โ€” take diagnostic bloods if clinically safe, then treat without waiting for results; ask about nitrous oxide exposure โ†’ Same-day
Anaemia is rarely a diagnosis in itself โ€” it is a sign of an underlying condition. Missing a GI malignancy behind iron-deficiency anaemia (IDA), or failing to recognise aplastic anaemia, has life-altering consequences. Under NICE NG12, adults with iron-deficiency anaemia are offered FIT, and a result of โ‰ฅ10 ยตg Hb/g triggers a suspected colorectal cancer referral; a negative FIT does not rule out referral if concern persists. Hb <70 g/L with significant symptoms needs same-day input, but Hb alone does not dictate 999 transfer or transfusion โ€” these decisions are clinical. Haemolysis can be life-threatening (e.g. TTP, haemolytic uraemic syndrome) and deteriorates rapidly without specialist treatment.
2
Diagnose

Confirm anaemia & characterise it โ€” MCV, indices and reticulocytes

Anaemia is confirmed against adult reference thresholds โ€” use local laboratory reference ranges. Use MCV, MCH, reticulocyte count, ferritin and the rest of the FBC to guide investigation. Mixed deficiencies may result in a normal MCV, and inflammation, CKD, reticulocytosis and recent transfusion can make indices misleading.
Adult thresholds (WHO)
Men: Hb <130 g/L  |  Women (non-pregnant): Hb <120 g/L โ€” use local laboratory reference ranges
Pregnancy (BSH 2020)
Hb <110 g/L (1st trimester), <105 g/L (2nd and 3rd trimesters). Postpartum thresholds vary by guideline and clinical context (BSH 2020 uses <100 g/L) โ€” not a WHO criterion. Below the pregnancy threshold: start oral iron, recheck in 2โ€“3 weeks and inform the midwife; Hb <70 g/L, significant symptoms, a rapid fall or late gestation (>34 weeks) โ†’ same-day maternity assessment (BSH 2020).
MCV <80 fL
Microcytic anaemia โ€” think IDA, thalassaemia, sideroblastic, chronic disease (can be). Most common in primary care = IDA.
MCV 80โ€“100 fL
Normocytic anaemia โ€” think anaemia of chronic disease (ACD), haemolysis, bone marrow failure, mixed deficiency, acute blood loss, CKD.
MCV >100 fL
Macrocytic anaemia โ€” think B12/folate deficiency, hypothyroidism, liver disease, alcohol, drugs (methotrexate, hydroxycarbamide), myelodysplasia.
First-line tests
Order FBC with indices first. Add a Reticulocyte count where haemolysis, blood loss, marrow failure or treatment response is suspected. Use a Blood film selectively: unexplained cytopenias, abnormal white cell or platelet counts, unexplained macrocytosis, suspected haemolysis, blasts, dysplasia or abnormal morphology, or severe or rapidly progressive anaemia.
Reticulocyte count
High reticulocytes โ†’ bone marrow responding (haemolysis, blood loss). Low/normal reticulocytes + anaemia โ†’ hypoproliferative (B12/folate/iron deficiency, bone marrow failure, CKD).
MCV is useful but does not dictate the whole work-up โ€” mixed deficiency, inflammation, CKD, reticulocytosis and recent transfusion can produce misleading indices, so read it with the MCH, reticulocytes, ferritin and the rest of the FBC. A raised reticulocyte count suggests haemolysis or haemorrhage; a low or normal count with anaemia suggests underproduction. When sent, the blood film adds morphological data (e.g. target cells in thalassaemia, hypersegmented neutrophils in B12 deficiency) that automated counters miss.
3
Diagnose

Classify the anaemia type โ€” targeted second-line investigations by MCV

Use the MCV with the other indices, reticulocytes and the clinical picture to guide second-line investigations.
Microcytic โ†’ IDA
Serum ferritin โ€” the most useful initial test for iron stores. Ferritin <15 ฮผg/L strongly supports absent iron stores; <30 ฮผg/L generally supports iron deficiency. A normal or raised ferritin does not exclude iron deficiency in inflammation, liver disease, CKD or malignancy; in inflammatory disease, ferritin up to 100 ฮผg/L with transferrin saturation <20% can represent iron deficiency (BSG 2021). Transferrin saturation, reticulocyte Hb or therapeutic response when ferritin is difficult to interpret. Then find the cause: Menorrhagia? GI loss? Coeliac? Haematuria?
Microcytic โ†’ Thalassaemia
Suspect if: normal/high ferritin, MCV disproportionately low, Mediterranean/SE Asian/African heritage, target cells on film. Hb electrophoresis / HPLC confirms. Refer to haematology for trait counselling if confirmed.
Normocytic โ†’ ACD
Most common in patients with known chronic disease (RA, IBD, CKD, malignancy). CRP / ESR elevated. Ferritin normal or raised (acute phase reactant). Renal function for CKD-related EPO deficiency.
Normocytic โ†’ Haemolysis
Bilirubin (unconjugated) LDH Haptoglobin (low in haemolysis) Direct Coombs test where immune haemolysis is suspected, with reticulocytes, blood film, and renal function and urinalysis where appropriate. Spherocytes / fragmented cells on film โ†’ urgent haematology.
Macrocytic โ†’ B12/Folate
Serum B12 Serum folate โ€” order together. Hypersegmented neutrophils on film highly specific for megaloblastic anaemia. Total B12 (use laboratory units, commonly ng/L or pmol/L; NICE NG239): <180 ng/L deficiency confirmed; 180โ€“350 ng/L indeterminate; >350 ng/L deficiency less likely. Do not routinely order Methylmalonic acid or Homocysteine for every indeterminate result โ€” use them selectively when the diagnosis remains uncertain (MMA is affected by renal impairment) or in suspected nitrous oxide toxicity.
Macrocytic โ†’ Other
TFTs (hypothyroidism), LFTs (liver disease/alcohol), medication review (methotrexate, hydroxycarbamide, antiretrovirals). Marked macrocytosis: review alcohol, liver disease, hypothyroidism, medications, reticulocytosis, B12/folate deficiency, haemolysis, marrow disease and nitrous oxide exposure. Refer to haematology if unexplained, persistent, progressive or with other cytopenias or abnormal film findings.
Ferritin is the single most useful confirmatory test for IDA but is an acute-phase reactant โ€” it can be falsely elevated in inflammation. A ferritin <30 ฮผg/L generally supports iron deficiency, and in inflammatory disease a ferritin up to 100 ฮผg/L with transferrin saturation <20% can still be IDA (BSG 2021). Coeliac serology (tTG-IgA with total IgA) should be checked in new IDA โ€” coeliac disease is frequently missed. B12 and folate should always be checked together as folate supplementation can mask B12 deficiency and precipitate subacute combined degeneration of the cord. MDS should be considered in older patients with unexplained, persistent or progressive macrocytosis, especially with other cytopenias.
4
Diagnose

Targeted examination โ€” find the cause, not just the sign

Examination confirms severity, guides urgency, and uncovers the underlying aetiology.
Vital signs
HR, BP, RR, SpO2. Interpret tachycardia and hypotension in context (age, baseline, sepsis, bleeding, medication, comorbidity). Severe hypoxia โ†’ emergency assessment.
Pallor
Conjunctival pallor (most reliable clinical sign), palmar creases, nail beds. Note: dark skin makes peripheral pallor unreliable.
Angular cheilitis / glossitis
Smooth red tongue (glossitis) + angular stomatitis โ†’ B12 or iron deficiency. Specifically ask about dysphagia (Plummer-Vinson/Patterson-Brown-Kelly syndrome in severe IDA).
Koilonychia
Spoon-shaped nails โ†’ chronic IDA. Less common but highly specific.
Jaundice / scleral icterus
Unconjugated hyperbilirubinaemia โ†’ haemolysis. Hepatosplenomegaly may also be present.
Lymphadenopathy / splenomegaly
Cervical, axillary, inguinal nodes + splenomegaly โ†’ haematological malignancy until proven otherwise. Measure and document node size.
Abdomen
Epigastric tenderness (peptic ulcer disease), mass (GI malignancy), ascites (liver disease/malignancy), organomegaly. Palpate for colonic masses in IDA aged โ‰ฅ40.
PR examination (when indicated)
When clinically indicated (eg rectal bleeding, change in bowel habit, suspected melaena or rectal mass) โ€” not mandatory for every patient. Rectal or anal mass or anal ulceration โ†’ consider a suspected cancer referral without waiting for FIT (NG12).
Neurological
B12 deficiency: peripheral neuropathy (reduced vibration sense/proprioception in legs), cognitive impairment, subacute combined degeneration signs โ€” must examine even if Hb normal (B12 can damage nerves before Hb falls). Ask about nitrous oxide exposure, particularly in younger adults โ€” serum B12 may be normal or borderline.
Examination in anaemia is often cursory in primary care. Clinical signs frequently identify the cause (glossitis = B12/iron, koilonychia = IDA, splenomegaly = haemolysis or haematological malignancy) and influence the urgency of referral. PR examination should be performed when clinically indicated, such as rectal bleeding or change in bowel habit โ€” rectal malignancy can be missed if it is omitted. Neurological examination in B12 deficiency is critical because subacute combined degeneration of the cord can occur at Hb levels that are near normal; delaying treatment causes irreversible damage.
5
Diagnose

Investigations โ€” find the underlying cause

Beyond the FBC, target investigations to find why the patient is anaemic.
Initial tests
FBC with indices Ferritin Reticulocyte count (where indicated) CRP / ESR LFTs TFTs U&Es + eGFR โ€” plus B12 and folate where macrocytosis, neurological symptoms or risk factors are present. Use a blood film selectively.
IDA (microcytic)
Ferritin (confirm) โ†’ tTG-IgA + total IgA (coeliac screen, do in all IDA) โ†’ FIT (NICE NG12 triage: โ‰ฅ10 ยตg Hb/g โ†’ suspected colorectal cancer pathway; a result below 10 does not exclude cancer) โ†’ GI investigation via the local suspected colorectal and upper-GI pathways โ€” not automatic OGD and colonoscopy from primary care. Men and postmenopausal women with confirmed IDA generally need it unless there is a clear alternative explanation; premenopausal women if aged 50 or over, with GI symptoms, or with a family history of colorectal cancer (BSG 2021), and consider it for disproportionate or recurrent IDA or a poor response โ†’ Urine dipstick for haematuria where clinically indicated. H. pylori is not a first-line IDA test โ€” if IDA remains unexplained after GI investigation (negative bidirectional endoscopy), offer non-invasive H. pylori testing and eradicate if positive (BSG); otherwise test and treat per dyspepsia/ulcer guidance.
B12 deficiency
Serum B12 (laboratory units, commonly ng/L or pmol/L): <180 ng/L deficiency confirmed; 180โ€“350 ng/L indeterminate; >350 ng/L deficiency less likely (NICE NG239) โ€” further testing (MMA/homocysteine) only selectively. Take diagnostic samples before treatment whenever clinically safe โ†’ Anti-intrinsic factor antibody if autoimmune gastritis is suspected โ€” positive supports pernicious anaemia; a negative result does not exclude it if suspicion remains high. Parietal cell antibodies are less specific and are not routine confirmatory tests.
Folate deficiency
Serum folate below the laboratory reference range = deficient. Investigate the cause rather than assuming diet: poor diet, alcohol, malabsorption, pregnancy, haemolysis, drugs (methotrexate, trimethoprim, phenytoin, sulfasalazine).
ACD / CKD
Ferritin normal or high. eGFR (NICE NG203): above 60 โ€” anaemia unlikely to be due to CKD, investigate other causes; 30โ€“60 โ€” investigate other causes, using clinical judgement on the extent; below 30 โ€” CKD more likely to contribute, but still consider other causes. Consider investigation and management when Hb is 110 g/L or lower or symptoms are attributable to anaemia. ESA treatment is initiated and monitored by renal services.
Do NOT routinely order
Bone marrow biopsy (specialist only). Erythropoietin levels (rarely actionable in primary care). Haptoglobin without clinical haemolysis suspicion.
Under NICE NG12, iron-deficiency anaemia in adults warrants FIT, with a suspected colorectal cancer referral at FIT โ‰ฅ10 ยตg Hb/g โ€” FIT is a triage test, not an exclusion test, and should not be the sole arbiter of referral (ACPGBI/BSG 2022). Coeliac serology is commonly overlooked. Parietal cell antibodies are not specific; NICE NG239 recommends considering anti-intrinsic factor antibody when autoimmune gastritis is suspected. Serum B12 can be indeterminate โ€” MMA or homocysteine can help selectively when the diagnosis remains uncertain, interpreting MMA with caution in renal impairment.
6
Refer

Referral criteria โ€” know who needs specialist input

Most anaemia is manageable in primary care. These patients need specialist input.
999
Collapse, shock or ongoing major haemorrhage; chest pain or suspected ACS (irrespective of Hb); severe symptomatic anaemia; severe hypoxia, confusion or heart failure; haematemesis, melaena or significant haematochezia with compromise.
Same-day
Rapidly falling Hb. Hb <70 g/L with significant symptoms. Suspected haemolysis with jaundice, haemoglobinuria or renal impairment. Pancytopenia with fever, bleeding, blasts or severe cytopenia. Neurological B12 symptoms. Suspected acute leukaemia or marrow failure. Postpartum anaemia with ongoing bleeding or significant symptoms.
Suspected cancer ยท haematology
Pancytopenia (urgent assessment). Suspected lymphoma / leukaemia (lymphadenopathy + anaemia + night sweats). Unexplained, persistent or progressive macrocytosis, or with other cytopenias or abnormal film (possible myelodysplasia). Unexplained normocytic anaemia with haematological abnormalities on film.
Suspected cancer ยท colorectal
IDA at any age: FIT, and a suspected cancer pathway referral if โ‰ฅ10 ยตg Hb/g (NICE NG12). Rectal bleeding (under 50 with abdominal pain or weight loss; any at 50+): FIT, and referral if โ‰ฅ10 ยตg Hb/g. Also FIT for change in bowel habit, abdominal mass, age 40+ with unexplained weight loss and abdominal pain, age 50+ with abdominal pain or weight loss, and age 60+ with anaemia even without iron deficiency. FIT is a triage test: below 10 does not exclude cancer โ€” refer on persistent symptoms, recurrent IDA or strong clinical concern; actively follow up unreturned kits; refer rectal or anal mass or anal ulceration without waiting for FIT.
Suspected cancer ยท upper GI
Unexplained IDA + dysphagia (any age), or aged 55 and over with weight loss plus upper abdominal pain, reflux or dyspepsia (NICE NG12). Suspected gastric malignancy.
Routine Haematology
Confirmed thalassaemia trait (genetic counselling + family screening). IDA with no measurable response to oral iron after review of adherence, diagnosis, ongoing loss and malabsorption. Haemolytic anaemia requiring ongoing monitoring. Pernicious anaemia (for initial specialist confirmation if needed locally).
Renal
CKD anaemia requiring ESA treatment โ€” initiated and monitored by renal services (NICE NG203).
Primary care
IDA with identified and treatable cause (menorrhagia, coeliac โ€” treat both). B12 deficiency โ€” manage in practice. Folate deficiency โ€” manage in practice. ACD with known stable underlying disease.
NICE NG12 (updated April 2026) offers FIT to adults with iron-deficiency anaemia and refers on the suspected colorectal cancer pathway at FIT โ‰ฅ10 ยตg Hb/g โ€” this applies even without overt GI symptoms, and FIT should not be the sole arbiter of referral. Failure to refer is a common cause of delayed cancer diagnosis complaints. Thalassaemia trait should be referred for genetic counselling, particularly for couples planning pregnancy (if both partners are carriers, 25% risk of thalassaemia major). IDA without a measurable Hb response within 2โ€“4 weeks of adequate oral iron must be reviewed and escalated โ€” causes include ongoing blood loss, malabsorption, and non-adherence.
7
Treat

Treatment pathways โ€” specific replacement by anaemia type

Treatment is cause-specific. Treat the underlying cause AND replace the deficiency.
Iron Deficiency Anaemia (IDA)
First-line (well tolerated)
Ferrous sulfate OD
One standard oral iron preparation once daily, providing approximately 50โ€“100 mg elemental iron (ferrous sulfate 200 mg โ‰ˆ 65 mg) โ€” BSG 2021. If not tolerated, consider alternate-day dosing, a different preparation or IV iron when clinically indicated. Routine vitamin C is not needed. Take away from tea, coffee, calcium and antacids; do not stop an essential PPI without review โ€” consider timing and indication.
Alternative preparations
Ferrous fumarate or gluconate OD
Use the local formulary for product choice and elemental iron content โ€” ferrous fumarate products vary substantially. Ferrous gluconate is an alternative. Once daily; alternate days if not tolerated.
Oral iron unsuitable
IV iron Local pathway
When oral iron is contraindicated, ineffective, not tolerated, unlikely to be absorbed, or too slow where rapid correction is clinically necessary โ€” not limited to IBD or CKD. Given via local infusion pathways; does not automatically require gastroenterology or haematology referral. Monitor for hypersensitivity. Ferric carboxymaltose (MHRA): risk of symptomatic hypophosphataemia, osteomalacia and fractures, particularly with repeated or high-dose treatment or risk factors (IBD, malabsorption, vitamin D deficiency, osteoporosis, hyperparathyroidism) โ€” monitor serum phosphate in those at risk.
Duration
Continue oral iron for 3 months after Hb normalises to replenish stores. Continue longer where ongoing loss, malabsorption or chronic disease persists.
Response monitoring
Recheck FBC at 2โ€“4 weeks (earlier in severe anaemia or if response is uncertain) โ€” expect a measurable Hb response within 2โ€“4 weeks. If not โ†’ review adherence, diagnosis, ongoing blood loss, malabsorption and concurrent disease.
Treat underlying cause
Menorrhagia โ†’ hormonal treatment / refer gynaecology. Coeliac โ†’ strict gluten-free diet (refer dietitian). H. pylori โ€” not a first-line IDA test; non-invasive testing and eradication if positive when IDA is unexplained after GI investigation (BSG), otherwise per dyspepsia/ulcer guidance. Iron treatment does not replace investigation of unexplained IDA.
B12 Deficiency
No neuro symptomsHydroxocobalamin 1 mg IM three times a week for 2 weeks, then 1 mg IM every 2โ€“3 months for life (SPC; NICE NG239) Lifelong IM replacement for autoimmune gastritis (pernicious anaemia), total gastrectomy or complete terminal ileal resection; other malabsorptive causes may need IM or oral treatment depending on the cause โ€” oral cyanocobalamin at least 1 mg daily when used for malabsorption. Diet-related deficiency only (absorption intact): oral cyanocobalamin 50โ€“150 micrograms daily between meals (SPC; NG239).
Neurological symptomsHydroxocobalamin 1 mg IM on alternate days until no further improvement (can be weeks), then every 2 months for life. Do not delay โ€” irreversible cord damage risk Do not delay treatment in suspected megaloblastic anaemia with neurological features; take diagnostic bloods first when clinically safe.
Pernicious anaemiaLifelong IM hydroxocobalamin every 2โ€“3 months (SPC; NG239). Do not routinely repeat serum B12 on IM replacement โ€” it mainly reflects treatment rather than tissue status. Routine gastric cancer surveillance is not recommended, but discuss the risk with the patient.
Folate Deficiency
Treatment
Folic acid 5 mg OD orally, commonly for 4 months โ€” duration should reflect the cause and local prescribing guidance. Do not give folic acid alone until B12 deficiency is excluded or treatment has started โ€” folic acid is not a substitute for B12 treatment โ€” giving folate alone in B12 deficiency can precipitate or worsen subacute combined degeneration of the cord.
Prevention (pregnancy)
Folic acid 400 mcg daily pre-conception and until 12 weeks. High-dose 5 mg daily if: previous or family history of NTD, diabetes, antiepileptics (not BMI alone โ€” NICE NG247).
Treat cause
Investigate the cause rather than assuming diet: alcohol, malabsorption, pregnancy, haemolysis, medications. Alcohol excess โ€” refer alcohol services. Malnutrition โ€” dietitian. Methotrexate โ€” review prescribing with the relevant specialist.
Anaemia of Chronic Disease
Principle
Treat the underlying condition โ€” optimise RA (DMARDs), IBD, CKD, malignancy. ACD does not respond to iron unless co-existing iron deficiency is confirmed โ€” in inflammation, interpret ferritin with transferrin saturation (BSG 2021).
CKD-related
Investigate and manage per NICE NG203 when Hb is 110 g/L or lower or symptoms are attributable to anaemia; correct iron deficiency first. ESA therapy is initiated and monitored by renal services. The aspirational Hb range of 100โ€“120 g/L applies to patients receiving ESA therapy, not all CKD patients โ€” avoid correcting Hb to normal with ESA.

Next steps: see Iron deficiency anaemia ยท Chronic kidney disease ยท Coeliac disease ยท Heavy menstrual bleeding ยท Haematological cancers

The BSG 2021 iron deficiency anaemia guideline advises one daily dose of a standard oral iron salt, with alternate-day dosing if not tolerated. IV iron corrects IDA faster than oral iron and is used when oral iron is contraindicated, ineffective, not tolerated or unlikely to be absorbed, or rapid correction is needed. For B12: autoimmune gastritis, total gastrectomy and complete terminal ileal resection need lifelong IM replacement; other causes may be treated IM or orally depending on the cause and clinical context (NICE NG239). Folate supplementation without checking B12 is a patient safety error โ€” the risk of precipitating or worsening subacute combined degeneration is well-documented.
8
Lifestyle

Non-pharmacological interventions โ€” dietary and lifestyle optimisation

Encourage a balanced diet containing iron, folate and B12. Address heavy menstrual bleeding, alcohol excess, restrictive diets, malabsorption and medication-related bleeding. Dietary advice complements, but does not replace, iron or vitamin replacement and investigation of the cause.
Iron-rich diet Red meat, liver, dark leafy greens (spinach, kale), legumes, fortified cereals.
Avoid inhibitors with iron Tea, coffee, calcium-rich foods, antacids all reduce iron absorption. Advise separating by 1โ€“2 hours from iron-rich meals or supplements. Do not stop an essential PPI without review.
B12-rich foods Meat, fish, eggs, dairy. Vegans/vegetarians must supplement (cyanocobalamin 10 mcg daily or 2000 mcg weekly) or consume fortified foods. Advise routinely โ€” B12 deficiency in vegans is preventable.
Folate-rich foods Green leafy vegetables, legumes, fortified cereals, liver. Advise good dietary intake โ€” particularly important in pregnancy, haemolytic states, and alcohol excess.
Alcohol reduction Alcohol causes folate deficiency, liver disease (macrocytosis), and GI bleeding (varices, gastritis). Refer to alcohol services if dependent.
Gluten-free diet (coeliac) Strict lifelong gluten-free diet restores duodenal absorption. Refer to registered dietitian for detailed guidance.
Manage heavy periods Menorrhagia is the leading cause of IDA in premenopausal women. Refer for gynaecology assessment. Hormonal treatment (LNG-IUS, combined pill) can reduce blood loss (NICE NG88).
Exercise titration In severe symptomatic anaemia, advise reduced physical exertion until Hb responds to treatment. As Hb corrects, gradual reintroduction of activity improves cardiovascular fitness and quality of life.
Dietary modifications alone rarely cure established anaemia but significantly aid recovery and prevent recurrence. Dietary advice complements, but does not replace, replacement therapy and investigation of the cause. In vegan patients, B12 supplementation prevents deficiency entirely and is far preferable to treating established neurological damage later. The LNG-IUS (Mirena coil) is an effective treatment for heavy menstrual bleeding (NICE NG88). Alcohol is a nutritional triple-threat in anaemia: it reduces folate absorption, impairs erythropoiesis directly, and causes GI haemorrhage.
9
Safety

Follow-up & monitoring โ€” ensure response and safety-net

Anaemia is not a one-appointment condition. Follow-up confirms resolution and catches complications.
2โ€“4 weeks (IDA)
Repeat FBC. Expect a measurable Hb response within 2โ€“4 weeks (review earlier in severe anaemia). If not: review adherence, diagnosis, ongoing blood loss, malabsorption and concurrent disease. Consider a different preparation or IV iron.
B12/folate
Repeat FBC according to clinical response rather than an automatic schedule. Review symptoms and treatment response at about 3 months, earlier if severe or clinically indicated, and at 1 month in pregnancy or breastfeeding (NICE NG239). Consider MMA/homocysteine only if symptoms persist and diagnostic uncertainty remains.
3 months
Hb should be normal. Review symptoms. Confirm cause is treated. For IDA: continue iron for further 3 months after normalisation to replenish stores. Check ferritin at this point.
6 months
Full review: Hb, ferritin (IDA). Do not routinely measure serum B12 during IM treatment. Ensure GI investigations completed and results reviewed. Confirm coeliac is adherent to GFD.
Longer term
Pernicious anaemia / B12 deficiency on injections: review symptoms and adherence; do not routinely repeat serum B12 on IM treatment. Coeliac disease: follow the local coeliac monitoring pathway โ€” annual FBC may be reasonable; tailor ferritin, B12, folate, tTG-IgA and bone health checks to the condition, symptoms, nutritional deficiencies and adherence.
Safety-net 999
Haemodynamic deterioration: feeling faint/collapse, very fast heart rate, black tarry stools, vomiting blood, chest pain with breathlessness.
Safety-net same-day GP
Worsening breathlessness at rest, new palpitations, ankle swelling, rapidly worsening fatigue suggesting haemorrhage. Any new neurological symptoms (weakness, numbness, coordination problems) in B12 deficiency โ€” risk of subacute cord degeneration.
Escalate if
No measurable response within 2โ€“4 weeks of adequate oral iron therapy. Recurrence of IDA after apparently successful treatment. New cytopenias (falling WCC or platelets) emerging during follow-up. Hb not normalising despite documented compliance.
Follow-up in anaemia serves three purposes: (1) confirm treatment response (a measurable Hb rise within 2โ€“4 weeks), (2) ensure the cause has been found and treated, and (3) detect complications early. IDA that fails to respond to oral iron is an important clinical signal โ€” non-adherence, ongoing blood loss, and malabsorption must all be addressed. Re-emerging IDA after treatment is common and often indicates inadequate investigation of the original cause. In B12 deficiency, neurological symptoms can progress even during treatment if the interval between injections is too long โ€” patients with neurological involvement should be on 2-monthly injections, not 3-monthly.
Educational use only. Pathway based on: NICE NG12 (Suspected cancer: recognition and referral, updated April 2026) ยท BSG 2021 iron deficiency anaemia guideline ยท NICE NG239 Vitamin B12 deficiency in over 16s (2024) ยท BSH UK guidelines on the management of iron deficiency in pregnancy (2020) ยท BSH Guidelines on the diagnosis and treatment of iron deficiency anaemia ยท BSH Guidelines for the diagnosis of cobalamin and folate disorders ยท NICE NG203 CKD (2021) ยท ACPGBI/BSG FIT in patients with signs or symptoms of suspected colorectal cancer (2022) ยท local formulary: nutrition and blood ยท MHRA Drug Safety Update: ferric carboxymaltose (Ferinject) โ€” hypophosphataemia, osteomalacia and fractures ยท WHO Haemoglobin concentration thresholds for diagnosis of anaemia (2011, international). Always adapt to individual patient context, local pathways, and formulary. This algorithm does not replace clinical judgement.