Hemoglobin Drop
ABCs & vitals
red flags
- hypotension · tachycardia
- chest pain · syncope
- active bleeding
- Hb drop >20 g/L within 24 to 48 hrs
- assess hemodynamic stability first
- review the Hb trend and rate of decline, compare with baseline
- repeat CBC if the result is unexpected
- check the sample was taken correctly (EDTA tube): exclude a spurious drop from a drip arm or lab error
HPI
- bleeding: melena, hematemesis, PR bleeding, hematuria, heavy menses, epistaxis
- hidden bleeding: abdominal pain, back / flank pain, thigh swelling, recent procedure or surgery, trauma or falls
- hemolysis: jaundice, dark urine, pale stools
- background: CKD, liver disease, known anemia, hemoglobinopathy
- meds: anticoagulants, antiplatelets, NSAIDs
examination
- general: pallor, jaundice, ecchymosis, purpura
- bleeding source: PR exam (melena / fresh blood), Foley bag (hematuria), procedure sites, large hematomas
- abdomen: tenderness, distension, hepatosplenomegaly
- limbs: thigh swelling, calf hematoma, signs of compartment syndrome
workup
bloods
- CBC + blood film
- PT / APTT / INR · fibrinogen
- group & screen
- reticulocytes → high = loss or hemolysis, low = underproduction
- LDH · bilirubin · haptoglobin
if bleeding suspected
- crossmatch blood
- CT abdomen / pelvis
- endoscopy referral if a GI source is suspected
if hemolysis suspected
- DAT (Coombs)
- blood film review
how to think
- acute Hb drop + shock → bleeding until proven otherwise
- acute Hb drop + jaundice → hemolysis until proven otherwise
- Hb drop after large fluid resuscitation → consider dilution
- Hb drop over weeks to months → work up as chronic anemia
management
if hypotensive
- 500 to 1000 mL crystalloid while assessing the cause
- crossmatch blood
- escalate urgently
active bleeding
- two large-bore cannulas, group & crossmatch
- hold anticoagulation, reverse when indicated
- identify and control the source
- transfuse as clinically indicated
suspected GI bleed
- IV PPI 80 mg stat → infusion 8 mg/h, escalate for urgent endoscopy
no active bleeding
- monitor the Hb trend
- investigate for occult bleeding
- investigate hemolysis
transfusion
- Hb <7 g/dL → transfuse most stable inpatients
- Hb <8 g/dL → ischemic heart disease / ACS, or symptomatic
- active bleeding → transfuse to the patient, not the number
- 1 unit, then recheck (expect ≈ 1 g/dL rise per unit), ask about prior transfusion reactions
calculator Glasgow-Blatchford (GI bleed) · MDCalc ↗︎
MOC pearl
rapid Hb drop → think bleeding, hemolysis, dilution, or lab error first. iron deficiency almost never explains a sudden inpatient Hb fall.
studying for the IM exam? the IM Rapid Review covers this in the same format. see the sample chapter.
Last reviewed · May 2026