CKD anaemia and iron management

01Purpose and principlesWhat the treatment does and how it fits into care.

Healthy kidneys support erythropoiesis through oxygen sensing and erythropoietin production. CKD adds shortened red-cell survival, inflammation-driven hepcidin, blood loss from sampling or dialysis and reduced iron absorption or availability. The resulting phenotype is often normocytic, but morphology is not a shortcut: microcytosis, macrocytosis, leukocyte or platelet abnormalities and a decline disproportionate to renal function require another explanation.

Iron indices answer different questions. Ferritin reflects storage but also behaves as an acute-phase reactant; transferrin saturation estimates circulating availability. A normal or high ferritin can therefore coexist with iron-restricted erythropoiesis. Treatment route depends on severity, dialysis modality, previous response, tolerance, venous access and preference, with resuscitation capability required for intravenous preparations.

Erythropoietic drugs aim to relieve symptoms, improve function and reduce transfusion, not restore a population-normal haemoglobin. ESA and HIF-PHI decisions need shared discussion of cardiovascular, thrombotic and cancer context. The team should use the lowest effective regimen, avoid rapid rises, monitor pressure and reassess any poor response before exposing the patient to progressively higher doses.

Key points

CKD anaemia is usually isolated, normocytic and hypoproliferative, becoming more plausible below eGFR 30 mL/min/1.73 m², but blood loss, iron or vitamin deficiency, inflammation, haemolysis and marrow disease must still be excluded.
The 2024 UK Kidney Association guideline advises investigation when haemoglobin is below 110 g/L or symptoms are attributable to anaemia, regardless of CKD stage or dialysis status.
Do not measure serum erythropoietin routinely: concentrations do not reliably separate renal anaemia or guide treatment.
Assess iron with red-cell indices and, where available, reticulocyte haemoglobin or hypochromic cells; otherwise combine transferrin saturation and ferritin with CRP because ferritin rises during inflammation.
Absolute iron deficiency requires a source assessment, especially gastrointestinal or menstrual blood loss; CKD causes impaired iron use but does not explain depleted stores by itself.
Correct iron deficiency before starting an ESA or HIF-prolyl-hydroxylase inhibitor; most haemodialysis patients need intravenous rather than oral iron.
For adults receiving an ESA, UKKA recommends a haemoglobin range of 100–120 g/L; normalising haemoglobin increases vascular and hypertensive harm without proven additional benefit.
ESA resistance is a diagnosis prompt, not a command to escalate indefinitely: check iron, infection, inflammation, bleeding, dialysis adequacy, hyperparathyroidism, adherence, haemolysis and marrow disease.
Roxadustat is a NICE option for eligible adults with symptomatic stage 3–5 CKD, no iron deficiency and no dialysis at initiation; use its current oral regimen and thrombotic safety framework through renal services.
Avoid transfusion when possible in a transplant candidate because HLA sensitisation can reduce future donor compatibility, but do not withhold life-saving blood for severe symptomatic anaemia or haemorrhage.

02Indications, selection and cautionsWho may benefit, who needs urgent treatment and important alternatives.

Renal pattern

Gradual isolated normocytic anaemia alongside advanced stable CKD, low reticulocyte response and no alternative cause supports deficient erythropoietic drive.

Iron-loss pattern

Low ferritin, falling MCV or MCH, pagophagia, restless legs, gastrointestinal symptoms or heavy menstrual bleeding indicates iron depletion needing source investigation.

Functional iron restriction

Low transferrin saturation with normal or raised ferritin and inflammation reflects iron sequestration and can blunt ESA response despite apparently adequate stores.

Anaemia symptoms

Exertional dyspnoea, fatigue, reduced concentration, dizziness, palpitations or angina depend on severity, speed of decline and cardiovascular reserve rather than one threshold.

Non-renal warning

Macrocytosis, pancytopenia, haemolytic indices, constitutional symptoms or a haemoglobin fall out of proportion to stable mild CKD should widen the differential immediately.

Treatment overshoot

New hypertension, headache, access thrombosis or a rapid haemoglobin rise during ESA or HIF-PHI treatment signals excess or a safety event requiring prompt review.

Red flags requiring action

Haemodynamic instability, active haemorrhage, syncope, ischaemic chest pain or severe hypoxia with anaemia needs urgent resuscitation, crossmatch and transfusion assessment rather than waiting for iron or ESA response.
A sudden haemoglobin fall with haemolysis, dialysis-circuit loss, retroperitoneal bleeding or gastrointestinal haemorrhage requires same-day cause control and cannot be labelled renal anaemia.
Severe uncontrolled hypertension or hypertensive neurological symptoms during ESA therapy require immediate blood-pressure management and specialist dose interruption.
A paradoxical haemoglobin fall with very low reticulocytes after prior ESA response raises rare antibody-mediated pure red-cell aplasia; stop the implicated strategy and seek specialist haematology-nephrology assessment.
Chest pain, unilateral swelling, acute dyspnoea or access dysfunction on ESA or HIF-PHI therapy may represent thrombosis and needs emergency evaluation.

03Assessment before treatmentTests and checks that guide safe selection.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Full blood count and blood filmFirst step
Why
Define severity, cell size and whether abnormalities extend beyond the erythroid line.
Interpretation and limitations
An isolated normocytic pattern fits renal anaemia; microcytosis, macrocytosis, cytopenias or abnormal cells prompt iron, vitamin, haemolysis, malignancy or marrow evaluation.
02
Reticulocyte count
Why
Assess marrow response to anaemia and identify unexpected underproduction or haemolytic compensation.
Interpretation and limitations
An inappropriately low response supports deficient production; high reticulocytes suggest bleeding, haemolysis or recovery, while profound reticulocytopenia on ESA raises pure red-cell aplasia concern.
03
Ferritin transferrin saturation and CRP
Why
Assess stored and circulating iron while recognising inflammation-related distortion.
Interpretation and limitations
Low ferritin supports absolute deficiency; low TSAT despite higher ferritin indicates functional restriction, and an inflammatory CRP makes ferritin alone particularly unreliable.
04
Reticulocyte haemoglobin or hypochromic red cells
Why
Measure recent iron availability to developing erythrocytes when timely laboratory processing supports the method.
Interpretation and limitations
Low cellular iron delivery can identify restricted erythropoiesis and guide replacement, but use the local assay definition and recognise thalassaemia interference.
05
B12 folate and haemolysis profile
Why
Exclude common correctable causes when indices, history or response is atypical.
Interpretation and limitations
Interpret B12 and folate clinically; bilirubin, LDH, haptoglobin and antiglobulin testing support haemolysis but CKD and inflammation can alter individual markers.
06
Blood-loss and malignancy assessment
Why
Find the cause of absolute iron depletion or an unexplained haemoglobin decline.
Interpretation and limitations
Review menstrual, gastrointestinal, procedural and dialysis losses and use urgent suspected-cancer or endoscopic pathways according to age, symptoms and iron-deficiency pattern.
07
Dialysis adequacy infection and PTH review
Why
Identify reversible drivers of ESA hyporesponsiveness in kidney-replacement therapy.
Interpretation and limitations
Inadequate clearance, access infection, chronic inflammation and severe hyperparathyroidism can all blunt response; escalating erythropoietic dose without addressing them compounds risk.

04Treatment approachPreparation, options, escalation and aftercare.

01EVALUATELow haemoglobin in CKDFirst stepHaemoglobin falls below 110 g/L or symptoms plausibly relate to anaemia.

1Assess urgency, bleeding, cardiovascular symptoms and trajectory, and compare renal stage with the severity and morphology of anaemia.
2Obtain FBC indices, reticulocytes, iron availability and CRP, adding B12, folate, haemolysis, paraprotein or marrow testing according to phenotype.
3Investigate absolute iron deficiency for a source rather than assigning it to CKD and review medicines, dialysis losses, inflammation and nutrition.
4Treat the identified cause, then reassess symptoms and haemoglobin before selecting renal-specific erythropoietic therapy.

02IRONRestore usable ironAbsolute deficiency or iron-restricted erythropoiesis contributes to symptoms or limits erythropoietic treatment.

1Use ferritin with TSAT or a validated cellular marker and confirm there is no active systemic infection before intravenous administration.
2For non-dialysis CKD or PD, choose oral versus IV iron through severity, tolerance, prior response, access and preference; most people on HD require IV iron.
3Administer the product-specific course where trained staff and resuscitation facilities can manage hypersensitivity and delayed reactions.
4Recheck haemoglobin and iron indices at the guideline interval, withholding or revising treatment before overload thresholds are crossed.

03ESAPersistent symptomatic renal anaemiaCorrectable causes and iron deficiency have been addressed but anaemia still impairs function or creates transfusion risk.

1Discuss anticipated symptom and transfusion benefit against hypertension, stroke, thrombosis, vascular-access and malignancy concerns.
2Start the local formulary ESA through renal services, selecting route and interval from dialysis modality, product and preference.
3Adjust gradually toward the adult 100–120 g/L range using haemoglobin trend and the lowest effective dose rather than a normal population target.
4EscalationIf response is poor or requirements rise, pause escalation and repeat the full iron, bleeding, infection, dialysis, PTH, adherence and marrow assessment.

04TRANSFUSEBlood is being consideredAnaemia is severe, rapidly symptomatic, haemorrhagic or unresponsive to slower treatment.

1Base urgency on haemodynamics, ischaemia, symptoms, ongoing loss and comorbidity rather than CKD-specific ESA targets.
2Discuss the transplant-sensitisation consequence with renal and transfusion teams when time permits and obtain appropriate compatibility samples.
3Use the current national transfusion pathway and reassess after each clinically indicated component, taking particular care with volume overload and potassium.
4After stabilisation, identify why iron or erythropoietic management failed and revise the prevention plan.

05Regimens, contraindications and interactionsTreatment details and the circumstances that modify them.

Replace iron in selected non-dialysis or peritoneal-dialysis patients when deficiency is mild enough and absorption or adherence is plausible.

Oral iron

Use the locally selected elemental-iron preparation and BNF regimen, adjusting frequency for tolerance and assessing response over the agreed trial interval.

Constipation, nausea, dark stools and interactions reduce adherence; oral treatment is often inadequate during marked inflammation or haemodialysis and does not remove the need to investigate blood loss.

Replete iron when oral therapy fails or is unsuitable and provide ongoing iron availability for most haemodialysis patients.

Intravenous iron

Calculate and administer the preparation-specific replacement or maintenance course under the current SmPC and renal protocol, with trained resuscitation support available.

Avoid during active infection, monitor ferritin and TSAT for excess, and watch hypersensitivity, extravasation and product-specific hypophosphataemia; formulations and maximum single doses are not interchangeable.

Reduce symptoms and transfusion need in appropriately selected CKD anaemia, particularly when transplant sensitisation should be avoided.

Erythropoiesis-stimulating agent

Initiate the locally commissioned epoetin or darbepoetin regimen after iron repletion and titrate from haemoglobin trend toward 100–120 g/L using the lowest effective dose.

Monitor hypertension, rapid haemoglobin rise, stroke, thrombosis and access events; avoid normalisation, review cancer context and investigate resistance before repeated dose escalation.

Offer a HIF-prolyl-hydroxylase inhibitor alternative for symptomatic renal anaemia within the commissioned population.

Roxadustat

For NICE-eligible non-dialysis stage 3–5 CKD without iron deficiency, use the SmPC three-times-weekly non-consecutive oral regimen and specialist titration algorithm.

Review thrombotic and cardiovascular risk, malignancy, infection and interacting medicines; monitor haemoglobin and iron, and stop if meaningful response is absent within the licensed assessment period.

06Complications, monitoring and follow-upAdverse effects, response and longer-term review.

Screen haemoglobin at least annually in G3 and at least twice yearly in G4–G5 not receiving kidney replacement therapy, increasing frequency with decline, symptoms or treatment.
During correction, measure haemoglobin often enough to prevent a rapid rise or overshoot; once stable, use the product and renal-service maintenance interval.
Monitor ferritin and TSAT or an available cellular iron marker during replacement, every 1–3 months for ongoing IV iron under UKKA guidance and with CRP when inflammation confounds interpretation.
Record blood pressure before and throughout ESA or HIF-PHI therapy and address missed antihypertensives, excess volume and dialysis prescription before assuming drug resistance.
Review symptoms, exercise capacity, transfusion avoidance and treatment burden as outcomes; laboratory movement without meaningful benefit may not justify escalating risk.
Audit rising ESA dose or falling response for occult bleeding, infection, underdialysis, iron restriction, severe PTH elevation, haemolysis, adherence and marrow disease.
Maintain a transplant-status flag in transfusion decisions and communicate any blood exposure to the transplant team for sensitisation follow-up.

07Special situationsVariants, exceptions and circumstances that change the usual approach.

Ferritin can conceal hunger

Inflammation raises storage ferritin while hepcidin prevents iron reaching erythroblasts, so TSAT or a cellular availability measure is essential.

Absolute deficiency needs a source

CKD impairs utilisation but does not cause empty iron stores by itself; gastrointestinal, menstrual and dialysis losses require explanation.

EPO levels add little

A concentration can be within a laboratory range yet inappropriately low for the degree of anaemia, making routine measurement clinically unhelpful.

The target is intentionally subnormal

ESA-associated vascular harm increases when clinicians pursue full normalisation; functional benefit with the lowest exposure is the safer objective.

Resistance is information

Higher dose requirement often signals iron restriction, inflammation, infection, blood loss, underdialysis or marrow disease and deserves diagnostic attention.

Transfusion changes transplant biology

Donor blood can generate HLA antibodies and narrow compatible organs, although emergency oxygen delivery still takes priority over future sensitisation risk.

08Common pitfallsFrequent interpretation and management errors.

01
Do not call every low haemoglobin in CKD ‘renal anaemia’ without indices, reticulocytes, iron studies and an alternative-cause screen.
02
Do not rely on ferritin alone when infection or inflammation can mask functional iron restriction.
03
Do not begin an ESA or HIF-PHI before correcting absolute iron deficiency and addressing blood loss.
04
Do not chase a normal adult haemoglobin with escalating ESA; the recommended treated range is deliberately lower.
05
Do not administer IV iron during active infection or without staff and facilities able to manage a hypersensitivity emergency.
06
Do not switch or dose erythropoietic products from memory because potencies, routes and intervals differ.
07
Do not avoid an urgently indicated transfusion solely to protect transplant candidacy, but involve renal and transfusion specialists as soon as feasible.