CBC – Hemoglobin Drop

ABCs
  • Check vitals → rule out shock or active bleeding
  • Repeat urgent CBC and compare with baseline
  • Ensure the sample is collected in an EDTA tube
HPI & examination
  • Symptoms: Chest tightness, SOB, fatigue
  • Bleeding
    • Melena, hematemesis
    • PR bleeding
    • Heavy menses
    • Hematuria
  • Appearance
    • Pallor, jaundice
    • Dark urine, pale stool
  • Bleeding tendency
    • Purpura, mucosal bleeding
    • Ecchymoses, joint bleeds
  • Focused exam
    • Pallor, jaundice
    • Ecchymosis/purpura/hematomas
  • Bedside checks
    • PR exam → melena / fresh blood
    • Foley → hematuria
  • Background
    • Known anemia
    • GI / liver / renal / thyroid disease
  • Medications → Antiplatelets, anticoagulants, NSAIDs
Common causes
CategoryCommon Causes
Acute blood lossGI bleed (most common), postoperative bleeding, trauma, hematuria, epistaxis
IatrogenicFrequent phlebotomy procedures
DilutionalIV fluids, resuscitation, transfusion
Reduced productionAnemia of inflammation, nutritional deficiency (iron, B12, folate), drug-induced marrow suppression
HemolysisDrug-induced (e.g., β-lactams, methyldopa), mechanical (valves, DIC, TTP)
Bone marrow failureAplastic anemia, myelodysplasia, hematologic malignancy
Management
  • If hypotensive → Give IV fluids (Normal saline)
  • If no active bleeding
    • Cross-match and reserve 2 PRBCs
    • Target: Hb >7 g/dL & Hb >8 g/dL (if CVD)
  • Suspected GI bleed
    • Start IV PPI: 80 mg stat → 40 mg IV BID or infusion 8 mg/hr
  • Before Transfusion
    • Send anemia + hemolysis workup
    • Ask about prior transfusion reactions
  • Investigations:
    • Anemia panel: CBC, blood film, iron profile, B12, folate
    • Hemolysis: Reticulocyte count, DAT, LDH, haptoglobin, LFT
    • Bleeding source: PR exam, urine R/M
  • Monitoring:
    • Monitor stool for melena / occult blood
    • Monitor urine for hematuria
    • Repeat CBC after transfusion

Studying for R1? The IM Rapid Review covers this in the same format — see the sample chapter.

Last reviewed · May 2026

MOC