Arterial Blood Gas

Test Code

ABG

Alias/See Also

ABG

CPT Codes
82803

Includes

pH, pCO2 (Partial Pressure of Carbon Dioxide), pO2 (Partial Pressure of Oxygen), HCO3 (Bicarbonate),Oxygen Saturation, Base Excess

Preferred Specimen

Blood gas syringe with heparin

Minimum Volume

1 mL

Instructions

Avoid getting air in syringe as this may affect results.

Transport Container

Heparinized syringe

Transport Temperature

Room Temperature

Specimen Stability

Room Temperature - 30 minutes

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Quantity Not Sufficient, clotted specimen, specimen stability exceeded during transport, venous contamination, air contamination, IV contamination

Methodology
Potentiometric and Amperometric

Setup Schedule

Daily upon receipt

Report Available

Upon completion of analysis

Limitations

Patients anesthetized with nitrous oxide or halothane may give unreliable results for pO2 due to the influence of these on the pO2 electrode. Results obtained from capillary samples, especially pO2 values, should be interpreted with caution.

Reference Range

Arterial pH:          7.34 - 7.44
Arterial PCO2:     35 - 45 mm Hg
Calc HCO3:         22 - 26 mmol/L
Arterial PO2:       75 - 100 mm Hg
O2 Saturation:     95 - 98 %
Base Excess:     - 2.4 to 2.3

Clinical Significance

Blood gases determine if a patient is in acidic or alkalotic state. The blood pH is protected and controlled by the blood buffers--bicarbonate/carbonic acid system, hemoglobin, protein, and phosphate. Of these, bicarbonate/carbonic acid system is the major buffer system because of the action of the lungs in getting rid of CO2 gas.

Used for the evaluation of the acid-base balance. Acidity or basicity is a sign of a disorder that can be of either respiratory or metabolic origin.

pCO2

CO2 is the waste product from metabolism and is excreted through the lungs. CO2 readily diffuses from the lung capillaries to the alveoli to be exhaled. pCO2 is used for evaluation of ventilation and the acid-base status, as it is a measure of the ability of the lungs to excrete carbon dioxide. pCO2 therefore gives an indication of how well the lungs are functioning. pCO2 is an important parameter for the evaluation of artificial/assisted ventilation therapy.

pO2

Used for a general evaluation of oxygen uptake in the lungs. Oxygen is carried to tissues as oxyhemoglobin in red blood cells. A small amount is dissolved in the plasma and is measured as pO2. A low pO2 indicates either poor perfusion across the alveolar walls or poor ventilation.

Base Excess

The base excess is the amount of acid or base (in mEq/liter) that would have to be added to the patient’s blood to bring it to a normal pH.

Oxygen Saturation

The oxygen saturation is a measure of the amount of oxygen in the blood that is combined with hemoglobin compared with the total amount of oxygen that can combine with hemoglobin. The ability of hemoglobin to bind oxygen is influenced by a number of factors such as pO2, pCO2, pH and 2,3-DPG.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.