Glasgow-Blatchford Score (GBS) Calculator

inputs

Blood urea

Haemoglobin

Systolic blood pressure

mmHg

Heart rate≥100 bpm scores 1 point

bpm

SexHaemoglobin thresholds differ by sex

Melena on presentation

Syncope

Hepatic disease (known or suspected)

Cardiac failure (known or suspected)

✓ when to use

Use in all adult patients presenting with suspected upper GI bleeding (haematemesis, melaena, coffee-ground vomiting) to guide disposition. GBS 0 patients can be discharged with outpatient endoscopy follow-up, avoiding unnecessary admission. GBS ≥1 generally warrants hospital assessment.

✗ when not to use

GBS predicts need for intervention, not mortality (AIMS65 or Rockall are better for mortality prediction). Not validated for lower GI bleeding. The score does not incorporate endoscopic findings — the complete Rockall score should be calculated post-endoscopy for re-bleeding risk. Not validated in children.

clinical pearls

A GBS of 0 is the most important result — it identifies patients who can go home. To score 0, the patient must have: urea <6.5, Hb ≥130 (men) or ≥120 (women), SBP ≥110, HR <100, no melena, no syncope, no liver disease, no cardiac failure.
GBS does not require endoscopy — it is a pre-endoscopy triage tool using only clinical and laboratory data available at presentation. This is its key advantage over the full Rockall score.
Urea rises after an upper GI bleed because digested blood provides a protein load. A disproportionately elevated urea relative to creatinine (urea:creatinine ratio >100:1 in SI units) supports upper rather than lower GI bleeding.
The haemoglobin thresholds are sex-specific — men score points at Hb <130 g/L, women at <120 g/L. This reflects different normal ranges and is important not to confuse.
Some UK trusts now use GBS ≤1 (rather than strictly 0) for outpatient management, based on data showing GBS 1 patients also have very low intervention rates. Check your local pathway.

✓ when to use

✗ when not to use

clinical pearls

A GBS of 0 is the most important result — it identifies patients who can go home. To score 0, the patient must have: urea <6.5, Hb ≥130 (men) or ≥120 (women), SBP ≥110, HR <100, no melena, no syncope, no liver disease, no cardiac failure.
GBS does not require endoscopy — it is a pre-endoscopy triage tool using only clinical and laboratory data available at presentation. This is its key advantage over the full Rockall score.
Urea rises after an upper GI bleed because digested blood provides a protein load. A disproportionately elevated urea relative to creatinine (urea:creatinine ratio >100:1 in SI units) supports upper rather than lower GI bleeding.
The haemoglobin thresholds are sex-specific — men score points at Hb <130 g/L, women at <120 g/L. This reflects different normal ranges and is important not to confuse.
Some UK trusts now use GBS ≤1 (rather than strictly 0) for outpatient management, based on data showing GBS 1 patients also have very low intervention rates. Check your local pathway.

Glasgow-Blatchford Score (GBS)

inputs

✓ when to use

✗ when not to use

clinical pearls

related tools