ABG chart: Free template download and use guide

Key Takeaways

An ABG chart is a diagnostic reference tool that displays arterial blood gas values (pH, PaO2, PaCO2, HCO3) in structured format for rapid clinical assessment.

Normal adult arterial pH ranges from 7.35-7.45; PaCO2 ranges from 35-45 mmHg; HCO3 ranges from 22-26 mEq/L. Labs may vary slightly, so always reference your facility’s specific ranges.

The ROME mnemonic (Respiratory Opposite, Metabolic Equal) helps clinicians identify whether a pH shift is driven by respiratory or metabolic causes, speeding bedside interpretation.

Practice management software like Pabau stores ABG results, interpretation notes, and clinical assessments in one secure patient record, so results, follow-up actions, and audit trails stay in one place.

An ABG chart, also called an arterial blood gas chart, puts every normal blood gas range and interpretation step in one place. Clinical staff use it as a bedside cheat sheet to read a result fast, without stopping to recall each value mid-shift.

It helps clinicians translate raw laboratory values into clinical action, separating respiratory from metabolic acid-base disorders in seconds. That speed matters when a delay in spotting hypoxemia or severe acidosis can escalate into an emergency.

This guide covers what a normal ABG chart contains, how to interpret results step by step using the ROME method, and how clinical teams can integrate ABG documentation into their practice workflows. We’ve included a free downloadable PDF template you can print for bedside reference.

What is an ABG chart?

An ABG chart is a structured diagnostic reference tool that displays the five core components of arterial blood gas analysis: pH, partial pressure of oxygen (PaO2), partial pressure of carbon dioxide (PaCO2), bicarbonate (HCO3), and oxygen saturation (SaO2). Each parameter exists within a specific normal range, and deviations signal respiratory or metabolic dysfunction.

The chart serves two clinical functions: it documents the patient’s actual laboratory values and provides normal reference ranges so clinicians can immediately spot abnormalities.

Unlike scattered notes or memory-dependent recall, a standardized chart ensures consistent interpretation across shifts and teams. This structured approach aligns with clinical governance standards that require consistent documentation and decision-making frameworks.

In clinical practice, the ABG chart often lives in two places: printed at the bedside for rapid reference during patient assessment, and integrated into the patient’s electronic record as part of their clinical documentation. Storing ABG results in a digital patient record in practice management software like Pabau lets every team member pull up the same values, so no one is working from a transcribed number that may be wrong.

How to interpret an ABG chart: Five-step method

ABG interpretation follows a systematic workflow that turns raw numbers into clinical meaning. This five-step method makes ABG interpretation easy to run at the bedside, in the order every clinician should follow:

1. Check the pH first. A pH below 7.35 signals acidemia; above 7.45 signals alkalemia. This single value tells you the direction of the acid-base disturbance and should guide all subsequent interpretation steps.
2. Look at PaCO2 and HCO3 to identify the primary disorder. If pH is low (acidemia), check whether PaCO2 is elevated (respiratory acidosis) or HCO3 is low (metabolic acidosis). If pH is high (alkalemia), check whether PaCO2 is low (respiratory alkalosis) or HCO3 is elevated (metabolic alkalosis).
3. Verify the expected respiratory or renal compensation. The body attempts to normalize pH by adjusting the opposing system. Winter’s formula and other compensation equations predict what the secondary system should do; if the actual value deviates significantly from the prediction, a mixed disorder is present.
4. Assess oxygenation separately. PaO2 and SaO2 describe oxygenation status independent of acid-base balance. A patient can have normal acid-base values but still be hypoxemic, so both must be evaluated.
5. Apply clinical context. The same ABG values carry different meaning in a chronic COPD patient versus an acute pneumonia admission. Chronic respiratory disease patients may have higher PaCO2 and lower pH at baseline; these “abnormal” values represent their steady state.

This systematic approach prevents the common error of fixating on a single abnormal value while missing the clinical pattern. Automated clinical workflows within your practice management system can trigger reminders to check ABG interpretation against a checklist, ensuring no step is skipped during high-acuity situations.

Normal ABG values reference table

This normal ABG values chart displays the standard adult arterial blood gas normal ranges. Always reference your facility’s laboratory values, as ranges may vary slightly based on equipment, altitude, and patient population. Pediatric and COPD-specific ranges appear below the standard adult values.

Pediatric adjustment: Pediatric serum bicarbonate ranges differ by age (e.g., 17-25 mmol/L at 12-24 months versus 22-26 mmol/L for adults). Always use age-stratified reference ranges when interpreting pediatric ABGs.

COPD caveat: Chronic COPD patients frequently maintain higher PaCO2 (45-65 mmHg) and lower pH (7.32-7.35) at baseline. These values are their “normal” steady state and should not be treated aggressively unless they represent acute decompensation above the patient’s baseline.

Who is this chart for?

ABG charts serve clinicians across specialties and settings:

• Respiratory therapists checking gas exchange during mechanical ventilation management.
• Emergency medicine physicians making rapid calls during acute decompensation.
• Physical therapists and sports medicine clinicians tracking oxygenation through rehabilitation.
• Integrative and functional medicine practitioners who order ABGs for metabolic assessment.

Nurses are among the heaviest users, which is why a clear ABG chart for nurses is a fixture on most units. Hospital-based staff, practice-based providers, and telemedicine practitioners all need rapid ABG interpretation too. A printed chart at the bedside removes the need to switch between software applications during urgent moments. On the other hand, a digital version stored in the patient record creates a permanent audit trail of when the test was ordered, what the results were, and how the clinician interpreted them.

Benefits of using an ABG chart

Standardized interpretation reduces clinical variation. When every team member follows the same five-step method, there is less room for the misreadings that make ABG a known source of diagnostic error. A shared chart also keeps interpretations of the same patient consistent from one shift to the next.

Compliance documentation becomes automatic. A structured ABG chart embedded in the patient record demonstrates that interpretation occurred, what decision-making framework was used, and what actions were taken. This satisfies Joint Commission and CQC documentation expectations without extra effort.

Workflow efficiency improves. Clinicians spend less time searching for reference values or second-guessing their interpretation. Faster interpretation translates directly to faster treatment decisions and reduced length of stay in acute settings.

Pro tip: Laminate and post it at the bedside

Understanding the ROME mnemonic: Respiratory opposite, metabolic equal

The ROME mnemonic simplifies compensation logic and speeds interpretation. Here’s how it works:

Respiratory changes move opposite to pH. When the respiratory system drives the disturbance, pH and PaCO2 move in opposite directions. High pH (alkalemia) pairs with low PaCO2 (hyperventilation = respiratory alkalosis). Low pH (acidemia) pairs with high PaCO2 (hypoventilation = respiratory acidosis).

Metabolic changes move equal to pH. When the metabolic system drives the disturbance, pH and HCO3 move in the same direction. High pH (alkalemia) pairs with high HCO3 (metabolic alkalosis). Low pH (acidemia) pairs with low HCO3 (metabolic acidosis).

This pattern recognition tool lets clinicians categorize a disorder in seconds. A patient with pH 7.50 and PaCO2 28 mmHg has respiratory alkalosis (high pH, low CO2, the opposite pattern). A patient with pH 7.28 and HCO3 16 mEq/L has metabolic acidosis (low pH, low HCO3, the equal pattern). Keeping ROME on your bedside chart removes the need to memorize four separate acid-base disorder definitions.

ROME vs the tic-tac-toe method: which to put on your chart

ROME is not the only shortcut. The tic-tac-toe method draws a three-column grid (pH, PaCO2, HCO3) and marks each value as acid, normal, or base. Values that line up in the same column reveal the primary disorder and whether compensation is underway. Both reach the same answer, so the choice comes down to how you think:

• Use ROME when you want a fast verbal check on which system is driving the pH.
• Use tic-tac-toe when a mixed disorder is likely and you need to see acidosis and alkalosis side by side in a grid.

Printing both on the same ABG chart gives staff a verbal mnemonic and a visual grid, so the interpretation holds up whether the clinician memorizes patterns or works better from a diagram.

Clinical governance and ABG documentation standards

Joint Commission and CQC expect clinical documentation to demonstrate systematic interpretation, not just raw numbers filed in a chart. A structured ABG chart, whether printed or digital, proves that clinical judgment was applied, risks were assessed, and a clear decision-making pathway was followed. This becomes especially important during audits or in medicolegal review.

Integrating ABG documentation into your practice management system ensures that no result sits unreviewed. Automated reminder workflows flag abnormal results for clinician action, creating an auditable record that the team responded appropriately. This transforms ABG from a standalone lab value into part of a coordinated care narrative.

How the body compensates: respiratory and renal responses

The body never tolerates pure acid-base disturbances for long. Within minutes to hours, the opposing system attempts compensation. An ABG compensation chart is only useful if you read these reflexive responses correctly, because a normal-appearing pH can still hide a mixed disorder.

Respiratory compensation for metabolic disturbances: If HCO3 drops (metabolic acidosis), the lungs hyperventilate to blow off CO2 and raise pH. Expected PaCO2 can be predicted using Winter’s formula: PaCO2 = 1.5 × [HCO3] + 8 ± 2. If the actual PaCO2 is higher than predicted, concurrent respiratory disease is present.

Renal compensation for respiratory disturbances: If PaCO2 rises (respiratory acidosis), the kidneys retain bicarbonate to raise pH. Acute respiratory acidosis produces minimal HCO3 rise; chronic respiratory acidosis (COPD, neuromuscular disease) produces a more pronounced HCO3 rise because the kidneys have time to adapt. This distinction is crucial. A COPD patient with pH 7.35 and PaCO2 65 may be in a comfortable steady state, not in crisis.

Reference materials such as the NCBI Nursing Fundamentals outline the expected compensation for each disorder, allowing clinicians to spot mixed disorders where two primary disturbances occur simultaneously.

Book a demo: Integrate ABG documentation into your practice workflow

See how Pabau streamlines clinical documentation

Store ABG results, interpretation notes, and follow-up actions in one secure digital record. Automated workflows remind teams when follow-up assessments are due, and audit trails document exactly when and how each result was interpreted.

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Putting the ABG chart to work

Used consistently, an ABG chart keeps interpretation aligned across the team, reduces diagnostic variation, and supports audit readiness. It saves time at the bedside and helps prevent the errors that follow a rushed reading. Book a demo to see how Pabau stores ABG results and automates follow-up in your practice workflow.

Recommended resources

Continue your research

Need a framework for systematic clinical note-taking? Safer clinical notes covers SOAP note structure and how to document clinical reasoning alongside ABG results.

Looking to automate follow-up assessments after abnormal ABGs? Automated workflows can trigger reminders when results fall outside normal range, ensuring no result gets missed.

Want to store ABG trends over time for chronic disease patients? Client records provide a chronological view of all ABG tests, interpretation notes, and clinical actions, supporting continuity of care across appointments.

Frequently Asked Questions