Advanced Calculator
Graph View
Example Data Table
| Case | pH | PaCO₂ | HCO₃ | Na | Cl | Likely Pattern |
|---|---|---|---|---|---|---|
| Example 1 | 7.25 | 28 | 12 | 140 | 100 | High gap metabolic acidosis |
| Example 2 | 7.51 | 48 | 37 | 138 | 92 | Metabolic alkalosis |
| Example 3 | 7.28 | 62 | 28 | 140 | 102 | Respiratory acidosis |
| Example 4 | 7.55 | 25 | 21 | 139 | 104 | Respiratory alkalosis |
Formula Used
Anion Gap: AG = Na - (Cl + HCO₃)
Albumin Corrected AG: Corrected AG = AG + 2.5 × (4 - albumin)
Delta Gap: Delta Gap = Corrected AG - Normal AG
Corrected HCO₃: Corrected HCO₃ = HCO₃ + Delta Gap
Delta Ratio: (Corrected AG - Normal AG) / (24 - HCO₃)
Winter Formula: Expected PaCO₂ = 1.5 × HCO₃ + 8 ± 2
Metabolic Alkalosis Compensation: Expected PaCO₂ = 40 + 0.6 × (HCO₃ - 24)
How to Use This Calculator
Enter the measured blood pH, PaCO₂, bicarbonate, sodium, chloride, potassium, and albumin. Use values from the same blood draw when possible. Then press the calculate button. The result appears above the form and below the page header. Review the primary pH status first. Then check the likely disorder. Next, compare measured PaCO₂ or bicarbonate with expected compensation. Finally, review the anion gap, corrected anion gap, delta gap, and delta ratio. Use the graph to see how measured values compare with common reference targets. Download the CSV or PDF for records, teaching, or later review.
Acid Base Disorder Chemistry Guide
Why Acid Base Balance Matters
Acid base balance shows how the body controls hydrogen ions. Small changes can affect enzymes, heart rhythm, breathing, and cell function. The calculator uses pH, carbon dioxide, bicarbonate, and electrolytes. These values describe respiratory and metabolic chemistry.
Reading the pH First
A low pH suggests acidemia. A high pH suggests alkalemia. A normal pH does not always mean normal chemistry. Two opposite disorders can offset each other. That is why compensation checks are important.
Metabolic and Respiratory Signals
Bicarbonate reflects the metabolic side. Carbon dioxide reflects the respiratory side. Low bicarbonate points toward metabolic acidosis. High bicarbonate points toward metabolic alkalosis. High carbon dioxide suggests respiratory acidosis. Low carbon dioxide suggests respiratory alkalosis.
Anion Gap Review
The anion gap estimates unmeasured ions. It uses sodium, chloride, and bicarbonate. Albumin correction improves interpretation when albumin is low. A high corrected gap can suggest added unmeasured acids.
Delta Ratio Review
The delta ratio compares gap change with bicarbonate fall. It helps screen for mixed metabolic disorders. A low ratio can suggest normal gap acidosis. A high ratio can suggest added metabolic alkalosis.
Safe Interpretation
This tool gives structured chemistry guidance. It cannot diagnose a patient alone. Always compare results with history, exam findings, oxygen status, lactate, kidney function, medications, and repeat testing when needed.
FAQs
1. What does this calculator estimate?
It estimates acid base status, likely primary disorder, compensation, anion gap, albumin corrected gap, delta gap, and delta ratio from common chemistry and blood gas values.
2. Can a normal pH still be abnormal?
Yes. A normal pH can hide mixed disorders. One process may push pH down while another pushes it up. Always review PaCO₂, bicarbonate, and anion gap.
3. Why is albumin correction included?
Albumin is an important unmeasured anion. Low albumin can make the anion gap look falsely normal. Correction helps reveal hidden high gap acidosis.
4. What is Winter formula?
Winter formula estimates expected PaCO₂ in metabolic acidosis. It helps decide whether respiratory compensation is appropriate or whether another respiratory disorder may coexist.
5. What does a high delta ratio mean?
A high delta ratio can suggest high anion gap acidosis with additional metabolic alkalosis. It should be interpreted with clinical details and repeat labs.
6. What does a low delta ratio mean?
A low delta ratio may suggest combined high gap and normal gap metabolic acidosis. Examples can include bicarbonate loss or renal tubular problems.
7. Is potassium required?
Potassium is not required for the basic anion gap formula shown here. It is included because potassium often matters clinically in acid base disorders.
8. Is this calculator a diagnosis?
No. It is an educational and screening tool. Diagnosis needs clinical assessment, repeat testing, history, medication review, and professional medical judgment.