MICA · FIRST-LINE LEARNING NOTES
Understand, prioritise and organise follow-up
Assess anaemia through its clinical tolerance, time course and mechanism. Iron deficiency needs confirmation, followed by investigation of its cause.
Assess clinical tolerance before classification
Look for breathlessness at rest, chest pain, syncope, active bleeding and circulatory instability: these require urgent assessment regardless of an isolated haemoglobin threshold. Compare previous blood counts and ask about menstrual or gastrointestinal blood loss, medicines that increase bleeding risk, diet and gastrointestinal surgery. Few symptoms may reflect gradual onset rather than a benign cause.
[1]Identify the mechanism
Review the whole blood count, including mean corpuscular volume and other cell lines; use reticulocytes and a blood film when relevant. Low ferritin supports iron deficiency, whereas inflammation can make normal or raised ferritin misleading. Transferrin saturation may clarify this. Consider vitamin B12 testing with macrocytosis, neurological features or malabsorption risk; B12 deficiency can also occur without macrocytosis.
[1][2]Classification does not replace identifying blood loss, reduced production or destruction. MCV guides reasoning, but mixed deficiency can mask macrocytosis. Ferritin that is not low during inflammation does not independently exclude iron deficiency. Consider clinical tolerance, haemoglobin trend and other blood cell lines rather than an isolated threshold.
[1][2]Treat and investigate the cause
Correcting deficiency does not replace investigation. In a man or postmenopausal woman with unexplained iron-deficiency anaemia, arrange appropriate gastrointestinal assessment and consider coeliac disease. Multiple cytopenias, a concerning blood film or suspected haemolysis require targeted referral. Do not automatically attribute anaemia in an older adult to age or kidney disease.
[1]- Investigate the cause of deficiency, including bleeding; a response to iron does not complete the workup.
- Neurological features with suspected B12 deficiency require treatment without unnecessary delay awaiting results.
- Arrange review of response, tolerance and adherence; reconsider the diagnosis if improvement does not occur.
Document an adequate response
Record the working cause, prescribed treatment and outstanding tests. Reassess symptoms, blood counts and tolerance according to severity and the chosen strategy. An inadequate response warrants review of adherence, absorption, ongoing loss, inflammation and the original diagnosis. Normal haemoglobin does not close the case when the cause of unexplained deficiency remains unresolved.
[1][2]A learning situation
FICTIONAL CASE · SELF-REFLECTION WITHOUT A SCORE
A 62-year-old man presents with fatigue, microcytic anaemia and low ferritin. He reports no abdominal pain or visible blood in his stool. Iron replacement is being considered.
Does the absence of gastrointestinal symptoms justify iron treatment alone?
Read the reasoning
No. Iron deficiency is supported, but its cause still needs investigation. Arrange appropriate gastrointestinal assessment, including consideration of occult loss and coeliac disease, while treating anaemia. Improvement with iron does not remove this need.
References and scope
- British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults ↗
- Vitamin B12 deficiency in over 16s: diagnosis and management (NG239) ↗
Original educational synthesis for adult first-line practice. International references must be interpreted with the clinical setting and local care pathways. Independent human scientific review remains to be confirmed.