Orderable Test Codes

LAB76 (arterial)
LAB79 (venous)

CPT Codes

82805

Synonyms

  • ABG
  • Arterial Blood Gases
  • Venous Blood Gases

Test Includes

Measured parameters include pH, pCO2, and Po2; calculated parameters include bicarbonate (HCO3), base excess or deficit (BE), oxygen saturation

Performing Laboratory / Facility

Ronald Reagan UCLA Medical Center Clinical Laboratory

Performing Section

Blood Gases

Availability

Daily, 24 hours (including holidays)

Turnaround Time

20 minutes from receipt in the Laboratory

Methodology

Specific Electrode

Use

Assess oxygenation of arterial blood and the body's acid-base balance

Limitations

Erroneous values can result from improper sample handling, excessive storage at room temperature before measurement, excessive storage at 2°C before measurement.

Contraindications

Relative contraindications include peripheral artery spasm.

Additional Information

Prior to sampling from the radial artery, a Modified Allen's Test should be performed to confirm adequate collateral circulation. Heparinized blood is required and may be obtained either from an artery or an "arterialized" capillary. Lithium heparin is generally used as an anticoagulant, it may be used in powder or liquid form. Errors have been reported from the excessive dilution of the sample with liquid heparin. Syringes and capillary tubes using powdered heparin obviate the need for concern regarding heparin dilution errors. Disposable kits are available that supply needles with inner cannula that minimize syringe-needle combined dead space, making a minimum sample size of 0.5 mL sufficient.
The most common causes of hypoxemia are:
• ventilation-perfusion (V/Q) abnormalities in the lungs
• physiologic shunting
• alveolar-capillary diffusion defects
• alveolar hypoventilation
• decreased inspired oxygen concentration
Interpretation of blood gases should start with the assessment of the ventilatory status by classification of the pCO2. A low pCO2 (<30 mm Hg) indicates alveolar hyperventilation. A high pCO2 (>50 mm Hg) indicates ventilatory failure. A pCO2 in the range of 30-50 mm Hg represents an acceptable level of alveolar ventilation. Because the lungs and the kidneys work together to achieve acid-base homeostasis, inspection of the arterial pH in conjunction with the pCO2 will allow determination of the origin of the acid-base disturbance. Acid-base disturbances can be a primary ventilatory problem (respiratory acidosis, respiratory alkalosis) or a primary metabolic problem (metabolic acidosis, metabolic alkalosis). Respiratory acid-base disturbances present for more than 24 hours will result in renal compensation by increasing or decreasing the plasma bicarbonate to normalize pH. Metabolic acid-base disturbances will result in partial or complete compensation by the respiratory system which increases or decreases alveolar ventilation (and thus the pCO2).

Specimen Type

Arterial blood, "arterialized" capillary blood, venous blood

Container

Dry Heparinized Syringes
Capillary Tube

Collection Instructions

Specimen drawn into air-free heparinized syringe with stopper. All specimens should be on ice and brought to the Laboratory immediately. For capillary collection the skin area to be punctured should be warmed a full 10 minutes. The puncture should be deep enough to allow a free flow of blood. Blood is then collected in heparinized capillary tubes, which should be at least 34 filled, capped and mixed well. All specimens must be labeled with patient's name, hospital number, and specimen source. Indicate on the requisition mode and percent of oxygen delivery or room air. Remove all air bubbles and needle. Cap before sending to the Laboratory.

Volume

2 mL blood

Minimum Volume

0.5 mL blood (when using 1 mL syringe)

Special Instructions

Arterial, whole blood is the specimen of choice. The blood is drawn in a plastic syringe precoated with heparin. Once collected, the specimen must be anaerobically maintained and kept on ice until analysis.

Shipping and Handling Instructions

Place specimen on ice immediately.

Causes for Rejection

Specimen not received on ice
air bubbles or clots in syringe

Reference Range

Normal values (arterial blood)
Analyte Values
pH 7.37 - 7.41
pCO2 38 - 42 mm Hg
pO2 98-118 mm Hg
Bicarbonate 22 - 26 mmol/L
Base excess -2 to 2 mmol/L
O2 saturation ≥95%
   
   
Normal values (venous blood)
Analyte Values
pH 7.30 - 7.40
pCO2 37 - 65 mm Hg
Bicarbonate 23 - 31 mmol/L

Critical Values

Arterial blood:  
   
Age: ≥6 months  
Analyte Values
pH <7.25, >7.55
pCO2 <25 mm Hg, >55 mm Hg
pO2 <50 mm Hg
   
Age: <6 months  
Analyte Values
pH <7.20, >7.55
pCO2 <25 mm Hg, >60 mm Hg
pO2:
patient not on O2
patient on O2		 <40 mm Hg, >150 mm Hg
>300 mm Hg
   
Cord blood:  
Analyte Values
pH <7.00
pCO2 ≥67
Base Excess < -12
   
   
   
Venous blood:  
   
Age: ≥6 months  
Analyte Values
pH <7.20, >7.60
pCO2 <25 mm Hg, >65 mm Hg
 
Age: <6 months  
Analyte Values
pH <7.10, >7.60
pCO2 <25 mm Hg, >65 mm Hg
   
Test Information

Orderable Test Codes

LAB76 (arterial)
LAB79 (venous)

CPT Codes

82805

Synonyms

  • ABG
  • Arterial Blood Gases
  • Venous Blood Gases

Test Includes

Measured parameters include pH, pCO2, and Po2; calculated parameters include bicarbonate (HCO3), base excess or deficit (BE), oxygen saturation

Performing Laboratory / Facility

Ronald Reagan UCLA Medical Center Clinical Laboratory

Performing Section

Blood Gases

Availability

Daily, 24 hours (including holidays)

Turnaround Time

20 minutes from receipt in the Laboratory

Methodology

Specific Electrode

Use

Assess oxygenation of arterial blood and the body's acid-base balance

Limitations

Erroneous values can result from improper sample handling, excessive storage at room temperature before measurement, excessive storage at 2°C before measurement.

Contraindications

Relative contraindications include peripheral artery spasm.

Additional Information

Prior to sampling from the radial artery, a Modified Allen's Test should be performed to confirm adequate collateral circulation. Heparinized blood is required and may be obtained either from an artery or an "arterialized" capillary. Lithium heparin is generally used as an anticoagulant, it may be used in powder or liquid form. Errors have been reported from the excessive dilution of the sample with liquid heparin. Syringes and capillary tubes using powdered heparin obviate the need for concern regarding heparin dilution errors. Disposable kits are available that supply needles with inner cannula that minimize syringe-needle combined dead space, making a minimum sample size of 0.5 mL sufficient.
The most common causes of hypoxemia are:
• ventilation-perfusion (V/Q) abnormalities in the lungs
• physiologic shunting
• alveolar-capillary diffusion defects
• alveolar hypoventilation
• decreased inspired oxygen concentration
Interpretation of blood gases should start with the assessment of the ventilatory status by classification of the pCO2. A low pCO2 (<30 mm Hg) indicates alveolar hyperventilation. A high pCO2 (>50 mm Hg) indicates ventilatory failure. A pCO2 in the range of 30-50 mm Hg represents an acceptable level of alveolar ventilation. Because the lungs and the kidneys work together to achieve acid-base homeostasis, inspection of the arterial pH in conjunction with the pCO2 will allow determination of the origin of the acid-base disturbance. Acid-base disturbances can be a primary ventilatory problem (respiratory acidosis, respiratory alkalosis) or a primary metabolic problem (metabolic acidosis, metabolic alkalosis). Respiratory acid-base disturbances present for more than 24 hours will result in renal compensation by increasing or decreasing the plasma bicarbonate to normalize pH. Metabolic acid-base disturbances will result in partial or complete compensation by the respiratory system which increases or decreases alveolar ventilation (and thus the pCO2).
Specimen Collection and Handling

Specimen Type

Arterial blood, "arterialized" capillary blood, venous blood

Container

Dry Heparinized Syringes
Capillary Tube

Collection Instructions

Specimen drawn into air-free heparinized syringe with stopper. All specimens should be on ice and brought to the Laboratory immediately. For capillary collection the skin area to be punctured should be warmed a full 10 minutes. The puncture should be deep enough to allow a free flow of blood. Blood is then collected in heparinized capillary tubes, which should be at least 34 filled, capped and mixed well. All specimens must be labeled with patient's name, hospital number, and specimen source. Indicate on the requisition mode and percent of oxygen delivery or room air. Remove all air bubbles and needle. Cap before sending to the Laboratory.

Volume

2 mL blood

Minimum Volume

0.5 mL blood (when using 1 mL syringe)

Special Instructions

Arterial, whole blood is the specimen of choice. The blood is drawn in a plastic syringe precoated with heparin. Once collected, the specimen must be anaerobically maintained and kept on ice until analysis.

Shipping and Handling Instructions

Place specimen on ice immediately.

Causes for Rejection

Specimen not received on ice
air bubbles or clots in syringe
Result Interpretation

Reference Range

Normal values (arterial blood)
Analyte Values
pH 7.37 - 7.41
pCO2 38 - 42 mm Hg
pO2 98-118 mm Hg
Bicarbonate 22 - 26 mmol/L
Base excess -2 to 2 mmol/L
O2 saturation ≥95%
   
   
Normal values (venous blood)
Analyte Values
pH 7.30 - 7.40
pCO2 37 - 65 mm Hg
Bicarbonate 23 - 31 mmol/L

Critical Values

Arterial blood:  
   
Age: ≥6 months  
Analyte Values
pH <7.25, >7.55
pCO2 <25 mm Hg, >55 mm Hg
pO2 <50 mm Hg
   
Age: <6 months  
Analyte Values
pH <7.20, >7.55
pCO2 <25 mm Hg, >60 mm Hg
pO2:
patient not on O2
patient on O2		 <40 mm Hg, >150 mm Hg
>300 mm Hg
   
Cord blood:  
Analyte Values
pH <7.00
pCO2 ≥67
Base Excess < -12
   
   
   
Venous blood:  
   
Age: ≥6 months  
Analyte Values
pH <7.20, >7.60
pCO2 <25 mm Hg, >65 mm Hg
 
Age: <6 months  
Analyte Values
pH <7.10, >7.60
pCO2 <25 mm Hg, >65 mm Hg
   

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