Arterial Blood Gas Calculator

This runs the arithmetic printed on a blood gas report: the Henderson-Hasselbalch relation checked in all three directions, the anion gap with and without the albumin correction, the delta ratio, and the expected compensation for a primary disorder you name. You enter the pH, PaCO2 and bicarbonate, or the electrolytes and albumin, and it returns each figure with the formula it used beside it. It does not decide which disorder is present and it does not diagnose anything, because thresholds, reference ranges and interpretation belong to the treating team.

Calculator Type

Runs the Henderson-Hasselbalch relation in all three directions so the pH, PaCO2 and bicarbonate on a report can be checked against one another.

As printed on the report.
In kPa, multiply by 7.50062 to get mmHg.
Most analysers calculate this from the pH and the PaCO2 rather than measuring it.
Widget

You name the primary disorder, this applies the published rule for it. It does not decide which disorder is present; that is a clinical judgement, not an arithmetic one.

This tool does not work out which disorder it is. Pick the one you want the compensation rule for.
As printed on the report.
In kPa, multiply by 7.50062 to get mmHg.
Most analysers calculate this from the pH and the PaCO2 rather than measuring it.
Widget
Albumin Unit

The anion gap from a chemistry panel, the same gap corrected for albumin, and the delta ratio against a reference gap you set.

Most analysers calculate this from the pH and the PaCO2 rather than measuring it.
Leave blank for the usual Na - (Cl + HCO3) form. Fill it in only if your laboratory includes potassium in its gap.
Leave at 4.0 g/dL for no correction. A low albumin hides part of the gap.
The delta ratio subtracts this. 12 is the classic teaching figure; many ion-selective electrode analysers run lower, so use your own.
Widget
Related Tools
GFR Calculator Mean Arterial Pressure Calculator Corrected Calcium Calculator