What type of blood sample is typically collected for blood gas analysis?

For blood gas analysis, an arterial blood sample is the preferred choice because it provides the most accurate and direct measurement of the gases (oxygen and carbon dioxide) present in arterial blood, which reflects the gas exchange and the respiratory function of the lungs. This type of sample allows healthcare professionals to assess the patient’s oxygenation, ventilation status, and acid-base balance.

Arterial blood samples are specifically collected because they contain the highest concentration of oxygen, as arterial blood is oxygen-rich and has not yet traveled to the tissues that will use the oxygen. This is essential for evaluating how well oxygen is being transported throughout the body and how effectively carbon dioxide is being expelled, which are critical components in diagnosing and managing respiratory or metabolic disorders.

In contrast, capillary blood samples, while useful for various tests, often do not provide the same level of accuracy for blood gas measurements due to potential contamination from interstitial fluid and the fact that they are typically taken from smaller blood vessels where gas exchange may not be fully representative of arterial levels. Venous blood samples are also less suitable because they reflect the metabolic state of the blood after it has passed through the tissues, resulting in lower oxygen levels and altered carbon dioxide levels compared to arterial blood. Whole blood samples refer to un