Kidney Disease Fatigue: The First Blood Test to Check
Updated: 4 hours ago
The short answer
If you have kidney disease and feel exhausted, start with hemoglobin, the oxygen-carrying red-cell measure on a complete blood count. Damaged kidneys send a weaker erythropoietin signal to the bone marrow, and anemia becomes more common as kidney function falls. Read hemoglobin beside ferritin and transferrin saturation, the two iron measures, before deciding what treatment fits. The treatment target is below the normal range because trials found that pushing hemoglobin back to normal did not reliably improve outcomes and sometimes caused harm.
What we cover
Why seven in ten people with kidney disease report fatigue, and what the transplant comparison does and does not say about age (Fletcher 2022)
How erythropoietin from the kidney tells the bone marrow to make red blood cells, and why that order weakens as kidney function falls (Besarab 1998)
How common anemia is at each stage, from about one in twelve at stage 1 to about half at stage 5, and how few people reported treatment (Stauffer 2014)
Ferritin versus transferrin saturation: iron in storage against iron in circulation, and why a normal ferritin can sit beside iron the marrow cannot reach (KDIGO 2026, Stancu 2018)
What happened when 2,141 people on dialysis got iron on a schedule instead of on a trigger (Macdougall 2019, PIVOTAL)
Why four randomized trials moved the hemoglobin target down: Normal Hematocrit 1998, CHOIR and CREATE 2006, TREAT 2009
The one action: a complete blood count, ferritin and transferrin saturation on the same draw, iron corrected before any injection decision
What to look at when all three numbers are fine: pain, mood, memory, sleep, thyroid, medications and restless legs (Boateng 2026, Safarpour 2023)
Timestamps
0:00 Fatigue and the first number to check
1:30 How kidneys signal red blood cell production
3:13 What transplant comparisons can tell us
4:44 Ferritin and iron saturation explained
6:46 What to ask at your next appointment
7:25 The monitored-iron trial in dialysis
8:35 Why medication targets stay below normal
11:34 Oral pills versus injections
12:39 What to investigate when tests are normal
15:44 Put your three numbers side by side
References
Fletcher BR, et al. PLoS Medicine, 2022. https://pubmed.ncbi.nlm.nih.gov/35385471/
Systematic review of 449 studies and 199,147 participants across 62 countries. Fatigue was reported by 70 percent of people with kidney disease not on dialysis and 70 percent on dialysis, against 48 percent after a transplant and 34 percent in people without kidney disease. Systematic review, observational.
Stauffer ME, Fan T. PLoS One, 2014. https://pubmed.ncbi.nlm.nih.gov/24392162/
US NHANES 2007 to 2010. Anemia in 15.4 percent of adults with kidney disease against 7.6 percent of the general population, rising from 8.4 percent at stage 1 to 53.4 percent at stage 5, and only 22.8 percent of those with both reported treatment in the prior three months, self-reported. Observational.
Stancu S, et al. J Med Life, 2018. https://pubmed.ncbi.nlm.nih.gov/30894885/
125 people with kidney disease stages 2 to 5 never treated with iron or injections. Observational.
Besarab A, et al. NEJM, 1998. https://pubmed.ncbi.nlm.nih.gov/9718377/
1,233 people on hemodialysis with heart disease, hematocrit target 42 percent against 30 percent. Randomized trial.
Singh AK, et al. NEJM, 2006. https://pubmed.ncbi.nlm.nih.gov/17108343/
CHOIR. 1,432 people with kidney disease not on dialysis, hemoglobin target 13.5 against 11.3 g/dL. Randomized trial.
Drueke TB, et al. NEJM, 2006. https://pubmed.ncbi.nlm.nih.gov/17108342/
CREATE. 603 people with kidney disease, target 13.0 to 15.0 against 10.5 to 11.5 g/dL. Randomized trial.
Pfeffer MA, et al. NEJM, 2009. https://pubmed.ncbi.nlm.nih.gov/19880844/
TREAT. 4,038 people with type 2 diabetes, kidney disease and anemia. Randomized trial.
Macdougall IC, et al. NEJM, 2019. https://pubmed.ncbi.nlm.nih.gov/30365356/
PIVOTAL. 2,141 people on hemodialysis, iron on a proactive monthly schedule against iron only when a number dropped. Randomized trial.
KDIGO 2026 Clinical Practice Guideline for Anemia in CKD, Executive Summary. https://doi.org/10.1016/j.kint.2025.06.005
Sets the hemoglobin target at or below 11.5 g/dL, typically 10 to 11.5, with treatment usually started between 8.5 and 10 g/dL in people not on dialysis and at or below 9 to 10 g/dL on dialysis; suggests an injection rather than an oral drug first-line; and defines iron-restricted red cell production as a ferritin of 100 to 300 ng/mL with transferrin saturation under 25 percent. Clinical guideline.
Boateng I, et al. Annals of Medicine, 2026. https://pubmed.ncbi.nlm.nih.gov/42334309/
NURTuRE-CKD. 2,996 people with kidney disease not on dialysis across 16 UK centres, followed a median 1.42 years. Observational.
Safarpour Y, et al. Tremor Other Hyperkinet Mov (NY), 2023. https://pubmed.ncbi.nlm.nih.gov/37008995/
Restless legs syndrome affects 15 to 30 percent of people on dialysis against 5 to 10 percent of the general population, and dopaminergic agents, gabapentin and pregabalin are reported as helpful. Narrative review.
One study explained in plain language every week, with sources attached, plus the free kidney health guide: https://guides.selfprinciple.org/kidney
This content is for educational purposes only and is not medical advice. Always consult your healthcare provider for individual care. The views expressed are Dr. Sean Hashmi's own and do not represent his employer.
Never start, stop, or change the dose of any prescription medication without consulting your physician.
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