Key Points
            - Use the highest‑yield diagnostic test early; do not let testing delay time‑critical therapy.
- Set objective targets and reassess frequently.
- Plan definitive source control or disease‑specific therapy when indicated; document follow‑up and patient education.
                                        Algorithm
            - Confirm IDA; search for bleeding source; treat underlying cause.
- Start oral iron on alternate days; consider IV iron if intolerance/malabsorption or urgent need.
- Reassess Hb/ferritin; continue 3 months after normalization to replenish stores.
                                        Clinical Synopsis & Reasoning
            Microcytic anemia with low ferritin and high transferrin indicates iron deficiency. Identify source of blood loss (GI, gynecologic), dose oral iron using alternate-day schedules for better absorption, use IV iron when intolerance or malabsorption, and transfuse based on symptoms and thresholds.
                                        Treatment Strategy & Disposition
            Stabilize ABCs. Initiate guideline‑concordant first‑line therapy with precise dosing and continuous monitoring. Escalate to advanced/procedural interventions based on explicit failure criteria. Define ICU, step‑down, and ward disposition triggers; involve specialty teams early.
                                        Epidemiology / Risk Factors
            - Risk varies by comorbidity and precipitants; see citations for condition‑specific data.
                                        Investigations
            
              
                | Test | Role / Rationale | Typical Findings | Notes | 
|---|
                
                  | CBC with indices, ferritin, iron/TIBC, CRP | Diagnosis | Low ferritin (<30 ng/mL) unless inflammatory state | Confirm deficiency | 
| FOBT and GI evaluation as indicated | Etiology | Occult GI bleeding | Bidirectional endoscopy in men/postmenopausal | 
| Celiac screen and gynecologic assessment | Alternatives/sources | Malabsorption or menorrhagia | — | 
                
              
             
                                        High-Risk & Disposition Triggers
            
              
                | Trigger | Why it matters | Action | 
|---|
                
                  | Hb <7–8 with symptoms | Hypoxia risk | Transfuse; search source | 
| Men/postmenopausal women | Occult GI cancer | Bidirectional endoscopy | 
                
              
             
                                        Pharmacology
            
              
                | Medication/Intervention | Mechanism | Onset | Role in Therapy | Limitations | 
|---|
                
                  | Oral ferrous sulfate 65 mg elemental iron once qod (alternate-day) | Repletion | Weeks | Improves absorption/tolerance | Vitamin C may help | 
| IV iron (ferric carboxymaltose/iron sucrose) | Parenteral repletion | Weeks | If PO intolerant/ineffective | Anaphylaxis rare | 
| Transfusion (symptomatic or Hb <7–8 g/dL) | Supportive | Immediate | Rapid correction | Balance risks | 
                
              
             
                                        Prognosis / Complications
            - Outcome depends on timeliness of diagnosis and definitive therapy; monitor for complications.
                                        Patient Education / Counseling
            - Provide red‑flag education, adherence guidance, and explicit return precautions; arrange timely specialty follow‑up.
                  
        
                  References
                      - Hematology guidance on IDA evaluation and treatment — Link