Male patient with mild chronic kidney disease (glomerular filtration rate 64 mL/min/1.73 m², creatinine 1.16 mg/dL), anemia (hemoglobin 11.8 g/dL, hematocrit 37%, normal mean corpuscular volume and mean corpuscular hemoglobin, low‑normal serum iron, ferritin 263 ng/mL, reticulocyte count 1.1%), vitamin B12 881 pg/mL, negative fecal immunochemical test, and prostate‑specific antigen 8.5 ng/mL—what is the most urgent problem and how should it be managed?

Elevated PSA is the Most Urgent Problem Requiring Immediate Urologic Evaluation

The PSA of 8.5 ng/mL in this patient represents the most urgent clinical priority and requires prompt urologic referral for digital rectal examination and consideration of prostate biopsy, as men with at least a 10-year life expectancy should undergo evaluation when PSA elevation could indicate prostate cancer. 1

Rationale for Prioritizing PSA Evaluation

• PSA 8.5 ng/mL significantly exceeds the 4.0 ng/mL threshold where approximately 25% of men with benign prostatic hyperplasia fall, making prostate cancer a serious diagnostic consideration that cannot be deferred 1
• The negative fecal immunochemical test effectively excludes gastrointestinal malignancy as a cause of the anemia, shifting focus to other potential malignancies 1
• Prostate cancer can cause anemia through bone marrow infiltration or chronic disease mechanisms, making the PSA elevation potentially explanatory for both problems 1

Immediate Actions for PSA Management

• Refer urgently to urology for digital rectal examination to assess for palpable nodules or induration suggesting locally advanced cancer 1
• Discuss benefits and risks of prostate biopsy with the patient, as definitive diagnosis requires tissue confirmation 1
• Consider PSA velocity, free/total PSA ratio, or PSA density measurements to improve diagnostic specificity if initial evaluation is equivocal 1

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Secondary Priority: Anemia of Chronic Kidney Disease

The anemia (Hgb 11.8 g/dL) with GFR 64 mL/min represents stage 3a CKD with anemia requiring systematic evaluation and iron supplementation before considering erythropoiesis-stimulating agents.

Diagnostic Interpretation of Laboratory Values

• The reticulocyte count of 1.1% is inappropriately low for the degree of anemia, indicating inadequate bone marrow response consistent with CKD-related erythropoietin deficiency 2
• Ferritin 263 ng/mL with serum iron 75 µg/dL suggests functional iron deficiency despite apparently adequate stores, as ferritin is an acute-phase reactant that may be elevated by inflammation 3
• Normal MCV and MCH exclude macrocytic anemia from B12/folate deficiency (B12 881 pg/mL is adequate) and rule out classic microcytic iron deficiency 2

Anemia Screening and Monitoring in CKD

• Hemoglobin should be checked at least annually in patients with GFR 30-59 mL/min/1.73 m² (stage 3 CKD) to detect progressive anemia 1
• The trending downward Hgb and Hct indicate progressive anemia requiring intervention before hemoglobin falls below 10 g/dL 3

Iron Status Assessment and Supplementation

Calculate transferrin saturation (TSAT) immediately using the formula: TSAT = (serum iron ÷ TIBC) × 100, as TSAT ≤20% defines iron deficiency in CKD regardless of ferritin level 1, 3

If TSAT ≤20%:

• Initiate intravenous iron supplementation with 200 mg IV weekly for 3 consecutive weeks (total 600 mg), as oral iron is poorly absorbed in CKD and inflammation 3
• Oral iron is not indicated for CKD patients due to impaired gastrointestinal absorption from hepcidin upregulation 1
• Reassess hemoglobin, ferritin, and TSAT approximately 2 months after completing the IV iron course 3

Expected Response to IV Iron:

• TSAT should rise above 20% and ferritin increase to 300-500 ng/mL range 3
• Hemoglobin should increase by at least 1 g/dL within 2-3 months if iron deficiency was contributing 3

Cardiac Function Considerations

• Iron deficiency impairs myocardial contractility and cardiac output independent of hemoglobin levels, so correcting iron deficiency may improve cardiac performance even before anemia fully resolves 4
• This is particularly relevant given the patient's CKD, which increases cardiovascular risk 4

When to Consider Erythropoiesis-Stimulating Agents

Defer ESA therapy until iron deficiency is corrected (TSAT >20% and ferritin >200 ng/mL), as adequate iron stores are required for effective erythropoiesis 3

ESA Initiation Criteria (all must be met):

• Hemoglobin remains <10 g/dL after iron repletion 3
• TSAT >20% and ferritin >200 ng/mL documented 3
• Rate of hemoglobin decline is concerning or patient has anemia-related symptoms (fatigue, dyspnea, reduced functional capacity) 3

ESA Dosing if Indicated:

• Darbepoetin 0.45 µg/kg subcutaneously weekly OR 0.75 µg/kg every 2 weeks 3
• Target hemoglobin 10-11 g/dL only, as higher targets increase mortality and cardiovascular risk 3
• Monitor hemoglobin weekly until stable, then monthly 3

Transfusion Avoidance

• Avoid routine transfusion at Hgb 11.8 g/dL unless severe symptoms (profound weakness, angina, resting dyspnea) or hemodynamic instability occur 3
• Transfusions carry alloimmunization risk, particularly problematic if future kidney transplantation is considered 3

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Additional Metabolic Bone Disease Screening

• Measure serum calcium, phosphate, PTH, and alkaline phosphatase once as baseline in this patient with GFR <45 mL/min/1.73 m² (stage 3b threshold) 1
• While this patient's GFR is 64 (stage 3a), screening becomes mandatory if GFR declines to <45 mL/min/1.73 m² 1

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Common Pitfalls to Avoid

• Do not assume ferritin >200 ng/mL excludes iron deficiency in CKD, as ferritin is an inflammatory marker and functional iron deficiency occurs with elevated ferritin 3
• Do not start ESA before correcting iron deficiency, as this leads to ESA resistance and poor outcomes 3
• Do not delay urologic evaluation while focusing solely on anemia management, as prostate cancer is potentially life-threatening and requires timely diagnosis 1
• Do not interpret reticulocyte count of 1.1% as "normal" in an anemic patient—this represents inadequate bone marrow response 2