An arterial blood gas (ABG) test is a critical diagnostic tool used to assess lung health, by measuring oxygen and carbon dioxide levels, and the body’s acid-base ratio. It provides real-time insights into lung function, respiratory efficiency, and metabolic status, making it essential in emergency care, critical care, and chronic respiratory conditions. In this article, we will discuss the purpose of the ABG test, what it measures, how to interpret arterial blood gas values, and its role in diagnosing and managing serious health conditions. Understanding blood gas levels helps both patients and caregivers make informed decisions about treatment and care.

Overview of Arterial Blood Gas (ABG) Testing

An arterial blood gas (ABG) test is a specialised blood test that measures the levels of oxygen , carbon dioxide , and the pH of the blood taken from an artery. Unlike routine blood tests drawn from veins, the ABG test uses arterial blood to provide a more accurate picture of how well the lungs are delivering oxygen and removing carbon dioxide. This test is often performed in hospital settings, particularly in intensive care units, emergency departments, and during surgical procedures. It is also used in patients with chronic lung conditions to monitor respiratory function and treatment response.

Components and Interpretation of Arterial Blood Gas Analysis

An arterial blood gas (ABG) analysis measures key elements in arterial blood to assess how well the lungs and kidneys are maintaining the body’s oxygenation, ventilation, and acid-base balance. These values are essential for diagnosing respiratory or metabolic conditions and for monitoring critically ill patients, where timely action is essential. The key components measured include:

pH

Indicates the acidity or alkalinity of the blood. 

• Normal range: 7.35 – 7.45
• Low pH = Acidosis
• High pH = Alkalosis

Partial Pressure of Oxygen

Measures the amount of oxygen dissolved in arterial blood. 

• Normal range: 75 – 100 mmHg
• Low Partial Pressure of Oxygen: May indicate hypoxaemia or impaired lung function

Partial Pressure of Carbon Dioxide

Reflects how well Carbon Dioxide is exhaled/being removed from the body. 

• Normal range: 35 – 45 mmHg
• High Partial Pressure of Carbon Dioxide: Respiratory acidosis
• Low Partial Pressure of Carbon Dioxide: Respiratory alkalosis

Bicarbonate

Represents the metabolic component of acid-base balance. 

• Normal range: 22 – 26 mEq/L
• Low Bicarbonate: Metabolic acidosis
• High Bicarbonate: Metabolic alkalosis

Oxygen Saturation 

Showsthe percentage of haemoglobin saturated with oxygen.

• Normal range: 95% – 100%

Oxygen Content

Refers to the total oxygen carried in the blood, including both bound and dissolved oxygen.

• Range depends on haemoglobin levels and Oxygen Saturation

Haemoglobin

Important for calculating Oxygen carrying capacity and oxygen delivery efficiency.

• Normal range varies by age and gender (typically 12–17 g/dL)

Clinical Use of Arterial Blood Gas Analysis

While arterial blood gas interpretation focuses on reading individual values, arterial blood gas analysis goes a step further, which is to apply those readings to assess overall patient health, monitor response to treatment, and guide clinical decision-making.

Key clinical uses of ABG analysis include:

• Diagnosing respiratory failure: ABG reports reveal how effectively the lungs are oxygenating the blood and removing carbon dioxide.
• Monitoring chronic lung diseases: In conditions such as COPD, regular analysis helps track disease progression and treatment effectiveness.
• Evaluating acid-base disorders: ABG values indicate whether an imbalance is of respiratory or metabolic origin.
• Guiding ventilator settings: ABG tests help determine how much support a patient needs during mechanical ventilation.
• Detecting co-existing conditions: ABG analysis, alongside clinical findings, may uncover mixed acid-base disturbances or underlying complications.

When and Why ABG Testing is Recommended

An arterial blood gas (ABG) test is widely used in emergency rooms, intensive care units, and hospital wards to assess oxygenation, ventilation, and acid-base balance. It provides immediate insight into a patient’s respiratory and metabolic function, guiding urgent interventions and long-term management. 

Common clinical uses and conditions where ABG testing is recommended include:

• Chronic lung diseases: Such as COPD and interstitial lung disease, where ABG helps monitor oxygen and carbon dioxide levels over time.
• Anaesthesia and post-operative care: To evaluate ventilation during surgery or recovery in high-risk patients.
• Metabolic disorders: Including diabetic ketoacidosis (DKA) and renal tubular acidosis (RTA), where acid-base imbalance must be closely tracked.
• Sepsis and shock – ABG aids in detecting tissue hypoxia and metabolic acidosis in cases like severe sepsis, septic shock, and hypovolaemic shock.
• Acute respiratory failure and ARDS – ABG reveals Partial Pressure of Oxygen and Partial Pressure of Carbon Dioxide levels to assess the severity of impaired gas exchange.
• Asthma attacks and airway obstruction – Helps determine Carbon Dioxide retention and oxygen deficiency.
• Cardiac arrest and acute heart failure – Used immediately post-resuscitation or in heart failure crises to assess acid-base status and ventilation needs.

Risks and Considerations of the ABG Test

While the arterial blood gas test is generally safe, it involves drawing blood from an artery, which carries more risk than a standard venous blood draw. Proper technique and post-procedure care are essential to minimise complications.

Common risks and considerations include:

• Discomfort or pain: The radial artery (commonly used) lies deeper than veins, making the procedure more uncomfortable.
• Bleeding or bruising: Minor bleeding or bruising at the puncture site is common, especially in patients on blood thinners.
• Arterial spasm: The artery may temporarily narrow in response to needle insertion, causing brief pain or difficulty collecting the sample.
• Hematoma formation: Accumulation of blood under the skin can occur if pressure is not applied properly after the test.
• Infection (rare): Sterile technique significantly reduces the risk.
• Risk for patients with clotting disorders: Additional precautions are needed in those with bleeding tendencies.

Note: To reduce the chance of complications, the ABG should always be performed by a trained healthcare professional using correct technique and post-procedure monitoring.

Why Choose MaxAtHome for ABG Testing

Getting an ABG test doesn't have to mean a stressful hospital visit. MaxAtHome brings expert diagnostic care to the doorstep, ensuring convenience, accuracy, and comfort, especially for patients who are critically ill or have mobility concerns. Here’s why MaxAtHome is trusted for arterial blood gas testing:

• Home sample collection by trained professionals: Avoid travel and waiting rooms; our skilled staff perform the test with precision and care at your location.
• Fast and accurate results: Your arterial blood gas report is processed using certified labs and shared promptly through a secure digital platform.
• Expert consultation: Based on your blood gas levels, follow-up guidance can be arranged through a home doctor visit or teleconsultation.
• Safe and hygienic process: Every step follows strict clinical protocols to minimise discomfort and ensure patient safety.
• Reliable service across cities: MaxAtHome operates in Delhi, Noida, Gurgaon, Mumbai, and more, offering timely diagnostic support when and where it’s needed.

Book your ABG test or medical consultation from the comfort of home by using our easy online platform or call 01244781023 to connect with a care advisor today.

Frequently Asked Questions (FAQs)

Q: What are the 6 steps in ABG analysis?

The six steps typically include:

• Assessing pH (acidic or alkaline)
• Evaluating Partial Pressure of Carbon Dioxide (respiratory component)
• Checking Bicarbonate (metabolic component)
• Identifying compensation
• Analysing Partial Pressure of Oxygen and oxygenation
• Determining the primary disorder (respiratory or metabolic)

Q: How is an ABG different from a venous blood gas test?

ABG uses arterial blood and gives precise data on oxygenation and ventilation, while venous blood gas (VBG) is easier to collect but less accurate for oxygen levels.

Q: What do high Partial Pressure of Carbon Dioxide levels indicate?

Elevated Partial Pressure of Carbon Dioxide typically points to hypoventilation or respiratory acidosis, often seen in lung conditions like COPD or during sedation.

Q: Can dehydration affect ABG values?

Yes, dehydration can alter blood gas levels, potentially leading to metabolic acidosis and affecting pH, bicarbonate, and other components.

Q: What is the cost of an ABG test?

The cost may vary depending on location and facility. MaxAtHome offers transparent pricing for home-based ABG testing—call 01244781023 for details.

Q: How do you treat abnormal ABG values?

Treatment depends on the underlying cause—options may include oxygen therapy, ventilation support, fluid replacement, or medication to correct acid-base imbalances.

Q: How accurate is the ABG test?

ABG testing is considered highly accurate for assessing gas exchange and acid-base status, especially when performed by trained professionals under controlled conditions.