Recomendaciones preanalíticas para la medición del equilibrio ácido-base y los gases en sangre. Recomendación (2018)

Blood gas analysis is a commonly ordered test in different hospital settings. The measurement of the parameters included in this analysis is vulnerable to a huge number of pre-analytical conditions. Laboratory staff are responsible for ensuring that these results accurately reflect the acid-base and oxygenation status of the patient. Despite many pre-analytical steps in blood gas testing being common to other laboratory tests, such as proper sample identification, others are particular for this determination, such as the stability of the analytes measured. The aim of this document is to provide recommendations for the control of the pre-analytical variables and other error sources related to blood gas analysis. These include the characteristics of the materials used to collect the blood samples (syringes, needles and anticoagulants), the sample types (arterial, venous and «arterialised» capillary blood), as well as the conditions for sample handling and transport, including the effect of the time between sampling and analysis, the temperature during transport, and the type of transport.