Calculator Form
Formula Used
Expected pH: pH = 6.1 + log10(HCO3 / (0.03 × PaCO2))
Anion gap: AG = Na - (Cl + HCO3)
Anion gap with potassium: AG = Na + K - (Cl + HCO3)
Albumin corrected gap: Corrected AG = AG + 2.5 × (4 - albumin)
Delta ratio: Delta ratio = (Corrected AG - 12) / (24 - HCO3)
Winter formula: Expected PaCO2 = 1.5 × HCO3 + 8 ± 2
Metabolic alkalosis compensation: Expected PaCO2 = 40 + 0.7 × (HCO3 - 24) ± 5
Calculated osmolality: 2 × Na + glucose / 18 + BUN / 2.8 + ethanol / 3.7
How to Use This Calculator
- Enter pH, PaCO2, and bicarbonate from the same blood gas period.
- Add sodium, potassium, chloride, albumin, lactate, glucose, and BUN.
- Enter measured osmolality when an osmolar gap review is needed.
- Press the calculate button to show the result above the form.
- Download the result as CSV or PDF for review records.
This tool is for structured review only. It does not provide diagnosis or treatment advice.
Example Data Table
| Scenario | pH | PaCO2 | HCO3 | Na | Cl | Albumin | Likely Pattern |
|---|---|---|---|---|---|---|---|
| High gap acidosis | 7.25 | 28 | 12 | 140 | 100 | 3.2 | Metabolic acidosis |
| Respiratory acidosis | 7.29 | 60 | 28 | 138 | 101 | 4.0 | Respiratory acidosis |
| Metabolic alkalosis | 7.52 | 48 | 38 | 139 | 91 | 4.1 | Metabolic alkalosis |
Acid Base Balance Review
Core Meaning
Acid base balance explains how the body controls hydrogen ions. It mainly depends on lungs, kidneys, buffers, and fluid volume. A small pH shift can reflect a large physiologic problem. This calculator turns common chemistry and blood gas values into a structured review. It checks pH, PaCO2, bicarbonate, electrolytes, albumin, lactate, and osmolality.
Why the Calculator Helps
Manual review can be confusing. A low pH may come from metabolic acid, retained carbon dioxide, or both. A high pH can reflect bicarbonate gain, acid loss, or excess ventilation. The tool compares measured values with expected compensation rules. It also estimates the anion gap and albumin corrected anion gap. These numbers help separate high gap acidosis from normal gap acidosis.
Advanced Interpretation
The delta ratio adds another layer. It compares the rise in corrected anion gap with the fall in bicarbonate. A low ratio can suggest an added normal gap acidosis. A high ratio can suggest metabolic alkalosis or chronic respiratory acidosis with a high gap process. The osmolar gap can support investigation of unmeasured osmoles when measured osmolality is available.
Use in Finance Records
The category here is Finance because reports may support billing notes, cost tracking, audit packets, or case summaries. The CSV export keeps values in a spreadsheet friendly format. The PDF button creates a compact report for documentation. It does not replace medical judgment.
Careful Limits
Results depend on correct units and valid sampling. Venous and arterial gases are not identical. Albumin correction changes the anion gap in low albumin states. Compensation equations are estimates, not strict laws. Clinical context, medications, renal function, oxygenation, and timing matter.
Best Practice
Enter fresh values from the same clinical period. Review the primary pattern first. Then check compensation. Next review corrected gap, delta ratio, lactate, and osmolar gap. Repeat the calculation after treatment or new labs. Use the output as a clear checklist for discussion, not as a final diagnosis.
Reading Trends
Trend review is often more useful than one isolated value. Falling lactate, closing anion gap, and improving bicarbonate may show recovery. A rising gap or widening osmolar gap needs attention. Compare outputs with symptoms, fluids, ventilation, and renal data before making plans during every review.
FAQs
What does this calculator estimate?
It estimates acid base status, primary pattern, compensation, anion gap, corrected anion gap, delta ratio, and osmolar gap using entered lab values.
Is this a diagnosis tool?
No. It is a structured calculation tool. Clinical review, patient history, timing, oxygenation, medications, and repeat testing are still required.
Why is albumin included?
Low albumin can hide an elevated anion gap. The calculator corrects the gap by adding 2.5 for each 1 g/dL albumin below 4.
What is Winter formula used for?
Winter formula estimates expected respiratory compensation in metabolic acidosis. It helps identify added respiratory acidosis or respiratory alkalosis.
What does a high delta ratio mean?
A high delta ratio can suggest added metabolic alkalosis or chronic respiratory acidosis with a high anion gap process.
When should measured osmolality be entered?
Enter it when you want osmolar gap review. It is useful when unmeasured osmoles or toxic alcohol exposure are being considered.
Can I save the result?
Yes. Use the CSV button for spreadsheet records. Use the PDF button for a compact printable report.
Why is the category listed as Finance?
The page can support finance records, billing summaries, case audits, or internal cost review files. The calculations remain clinical chemistry based.