ICU Map

Delta Ratio

Compares the rise in anion gap to the fall in bicarbonate, to detect a second metabolic process hiding behind a high-anion-gap acidosis.

Formula

Delta ratio = (Anion gap − 12) / (24 − HCO3)

Result

Enter all values to see the result.

Limitations

  • Only meaningful when a high-anion-gap metabolic acidosis is already present — applying it without one produces a number without a valid interpretation.
  • Assumes fixed normal reference values (anion gap 12, bicarbonate 24) that vary somewhat by laboratory.
  • A ratio in the 'typical' range doesn't rule out a second process of similar magnitude in the opposite direction — it only means the two are not obviously mismatched.

References

  • Standard derivation comparing anion gap excess to bicarbonate deficit; see also Delta Gap and Mixed Acid-Base Disorders in the Physiology Library.

Clinical Context & Relevant Topics (3)

Disease Reference
Acid-Base Disorders: Comprehensive Critical Care Approach

Stepwise 6-step interpretation algorithm, compensation formulas, albumin-corrected anion gap, delta ratio, and Stewart physicochemical (SID) principles.

Open Topic →
Metabolic Acidosis: HAGMA, NAGMA, & Bicarbonate Evidence

Differential diagnosis (GOLD MARK vs HARDCARP), toxic alcohol osmolar gaps, Urine Anion Gap, and current sodium bicarbonate evidence including BICAR-ICU and BICARICU-2.

Open Topic →
Diabetic Ketoacidosis (DKA)

Pathophysiology, SGLT2i euglycemic DKA, balanced fluid resuscitation, potassium-before-insulin safety rules, dextrose addition kinetics, and subcutaneous transition.

Open Topic →

Relevant Clinical Pathways (6)

Decision Protocols
Renal Replacement Therapy & CRRT Initiation

From urgent 'AEIOU' indication screening and modality selection to vascular access, dosing, and anticoagulation.

Launch Pathway →
Acute Severe Metabolic Acidosis Evaluation

From primary disorder confirmation and Anion Gap calculation to Winter's compensation, delta ratio, and targeted source control.

Launch Pathway →