Nursing care
Anemia nursing care: what to assess and what to do first
Written and reviewed by Dana Whitfield, RN, MSN · 5 min read · Updated September 2026
Short answer
Anemia nursing care starts with identifying the cause, since interventions differ for iron deficiency, B12 deficiency and chronic disease. A key teaching point clinicians miss is that iron should be taken with vitamin C, not calcium, since calcium blocks absorption while vitamin C enhances it, and black stools on oral iron are an expected side effect, not a sign of GI bleeding.
What it is and why it happens
Anemia is a reduction in red blood cells, haemoglobin or both, below the level needed to meet the body's oxygen demands. It is not a single disease but a finding with many causes: decreased production, as in iron or B12 deficiency and bone marrow suppression; increased destruction, as in haemolytic anaemia and sickle cell disease; and blood loss, acute or chronic.
Iron deficiency is the most common cause worldwide and results from inadequate dietary intake, malabsorption, or chronic blood loss, menstrual, gastrointestinal or occult. Because the body needs iron to build haemoglobin, a deficiency reduces the oxygen-carrying capacity of every red cell produced, and the resulting cells are typically small and pale, microcytic and hypochromic, on a blood film.
How it presents — what you will actually see
Classic findings reflect reduced oxygen delivery: pallor of the skin, conjunctiva and nail beds, fatigue, exertional dyspnoea, and tachycardia as the heart compensates for lower oxygen-carrying capacity. Patients may report dizziness on standing and cold intolerance. Severe or long-standing anaemia can produce a systolic flow murmur as blood viscosity drops.
Findings vary by cause. Iron deficiency can cause brittle nails, spoon-shaped nails in severe cases, and pica, cravings for non-food substances such as ice or starch. B12 deficiency adds neurological signs, paraesthesia, unsteady gait and glossitis, that iron deficiency does not produce. Anaemia of chronic disease, seen with renal failure or malignancy, tends to present more subtly, layered on top of the symptoms of the underlying illness.
Nursing assessment priorities
Assess vital signs for compensatory tachycardia and orthostatic changes, and inspect conjunctiva, nail beds and skin for pallor, findings that are more reliable in patients with darker skin tones than facial colour alone. Ask about fatigue's impact on activities of daily living, since functional decline often brings the anaemia to attention before labs do.
Review the CBC trend, haemoglobin, haematocrit, MCV and reticulocyte count, to identify the type of anaemia and whether the bone marrow is compensating. Ask about diet, menstrual history, and any melena, haematochezia or haematemesis to identify a bleeding source. For a patient already on oral iron, distinguish expected black, tarry-looking stool from oral iron, which is dark and formed, from true melena, which is black, tarry and foul-smelling and signals active GI bleeding.
Interventions and what to do first
For symptomatic anaemia, prioritise oxygenation and activity pacing: space out care activities, provide rest periods, and use supplemental oxygen if the patient is hypoxic or significantly tachycardic. Administer packed red blood cells as ordered for symptomatic or severe anaemia, monitoring for transfusion reaction throughout.
For iron deficiency, administer oral iron with vitamin C, such as a glass of orange juice, since vitamin C converts iron to a form the gut absorbs more readily. Do not give iron with calcium-containing foods or antacids, milk, cheese or calcium supplements, since calcium competes with iron for absorption and significantly reduces the dose the patient actually gets. Give iron on an empty stomach when tolerated, and switch to taking it with a small amount of food only if GI upset limits adherence.
Complications to watch for
Severe or rapidly developing anaemia can precipitate high-output heart failure, since the heart compensates for low oxygen-carrying capacity by increasing rate and stroke volume, a burden it cannot sustain indefinitely. Watch for worsening dyspnoea, jugular venous distension and peripheral oedema in patients with chronic, severe anaemia.
During transfusion, monitor for acute haemolytic reaction, fever, chills, back pain and hypotension, which requires stopping the transfusion immediately, and for transfusion-associated circulatory overload, particularly in older adults or those with cardiac or renal impairment. In B12 deficiency, delayed treatment risks permanent neurological damage, so neurological symptoms warrant prompt escalation rather than a wait-and-see approach.
Patient teaching before discharge
Teach patients to take oral iron with vitamin C, a glass of orange juice or a vitamin C supplement, to improve absorption, and to avoid taking it alongside milk, calcium supplements or antacids, which block absorption. Reassure them that stools will turn black and may become more solid on iron therapy, this is an expected effect of the iron itself and not a sign of bleeding, and that it resolves once iron is stopped.
Explain that GI upset, nausea or constipation, is common with oral iron and can be managed by taking the dose with a small amount of food if it cannot otherwise be tolerated, without giving up the therapy altogether. Cover dietary sources of iron, red meat, leafy greens and fortified cereals, and explain that response to oral iron takes weeks, with haemoglobin improving before the patient necessarily feels back to normal. Set the expectation that follow-up labs are needed to confirm the anaemia is resolving and to identify whether a bleeding source needs further investigation.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our med-surg practice questions are the closest set to what this page covers.
One question from the med-surg set
A client with chronic obstructive pulmonary disease has an oxygen saturation of 88% on 2 L/min via nasal cannula and is alert with no distress. What should the nurse do first?
Rationale
In COPD a saturation of 88–92% is the therapeutic target, not an emergency, and this client is alert with no distress. The first action is the independent nursing intervention that is least invasive and most likely to help: sit them up and reassess. Turning the oxygen up to 6 L/min risks blunting the hypoxic drive, and calling rapid response or drawing an ABG escalates ahead of an assessment you have not finished.
Answer: B
Common questions
Why should iron supplements not be taken with calcium?
Calcium competes with iron for the same absorption pathway in the small intestine, so taking them together significantly reduces how much iron the body actually absorbs. Patients should separate calcium-containing foods or supplements from their iron dose by at least a couple of hours.
Is black stool on iron supplements a sign of GI bleeding?
No, black or dark stool is an expected and harmless effect of oral iron and does not indicate bleeding. True melena from a GI bleed is black, tarry and has a distinctive foul odour, and is usually accompanied by other signs such as hypotension or a falling haemoglobin, which oral-iron-related stool changes are not.
What lab values distinguish iron deficiency anaemia from B12 deficiency?
Iron deficiency produces microcytic, hypochromic red cells with a low MCV, while B12 deficiency produces macrocytic red cells with a high MCV. Iron studies (ferritin, TIBC) and B12 levels confirm the specific deficiency, and B12 deficiency also carries neurological signs that iron deficiency does not.
What should I monitor during a packed red blood cell transfusion for anaemia?
Monitor vital signs before the transfusion and at regular intervals throughout, watching for fever, chills, back pain, hypotension or dyspnoea, which suggest a transfusion reaction. Stay with the patient for the first 15 minutes, since most acute reactions occur early in the infusion.
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