Clinics and Departments

Laboratory Services

Lab Dept:

Chemistry

Test Name:

CAPILLARY BLOOD GAS (CBG)

General Information

Lab Order Codes:

CBG

Synonyms:

CBG

CPT Codes:

82803 – Gases, blood, any combination of pH, pCO2,pO2, CO2, HCO3 (including calculated O2 saturation)

Test Includes:

pH (no units), pCO2 measured in mmHg, HCO3 and BE measured in mmol/L, Temperature (C) and ST (specimen type)

Logistics

Test Indications:

Capillary blood gas determinations are useful in monitoring neonates or other patients when arterial collection is not practical. Arteriolization of the capillary bed yields pH and pCO2 comparabe to arterial blood. Useful for evaluating oxygen and carbon dioxide gas exchange; respiratory function, including hypoxia; and acid/base balance. It is also useful in assessment of asthma; chronic obstructive pulmonary disease and other types of lung disease; embolism.

Lab Testing Sections:

Chemistry

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

30 minutes

Special Instructions:

See Collection and Patient Preparation

Specimen

Specimen Type:

Whole blood

Container:

Lithium Heparinized Capillary blood gas tube tightly capped with internal mixing flea.

Draw Volume:

0.2 mL blood (Minimum: 0.1 mL)

Note: Submission of 0.1 mL of blood in one capillary tube does not allow for repeat analysis.

Processed Volume:

0.1 mL blood per analysis

Collection:

Perform a capillary puncture from an arteriolized site. Fill 2 capillary tubes completely without introducing air bubbles. Cap both ends and mix 20 times by inversion. Forward immediately at ambient temperature only. Do not expose the specimen to air.

Special Processing:

Lab Staff: Deliver the specimen to the blood gas testing station. Testing must be completed within 15 minutes of collection or the sample should be immersed in an ice bath as soon as possible.

Patient Preparation:

The skin area to be punctured should be warmed to no more than 42C for 3-10 minutes by applying an infant heal warmer. The patient should be in a relaxed and steady state

Sample Rejection:

Clotted specimen; unlabeled specimen or mislabeled specimens; specimens >30 minutes old; specimen contaminated with large air bubbles

Interpretive

Reference Range:

pH:

7.35 – 7.45

PCO2:

Males:

35 – 48 mm Hg

Females:

32 – 45 mm Hg

HCO3:

22 – 27 mEq/L

Base Excess:

Newborn (0 – 7 days):

-10 to -2 mmol/L

Infant (1 week – 1 year):

-7 to –1 mmol/L

Child (1 – 16 years):

-4 to +2 mmol/L

Adult (>16 years):

-3 to +3 mmol/L

Critical Values:

pCO2: <15 or >70 mm Hg

pH: <7.2 or >7.6

Limitations:

N/A

Methodology:

Ion-Selective Electrode, HCO3 and BE by calculation

References:

Tietz, Norbert (1995) Clinical Guide to Laboratory Tests, 3rd edition, WB Saunders Co, pp 1081-1084

ABL 800 FLEX Operator’s Manual, Publication 200802, Edition H, Code Number 990-315, 2008 Radiometer Medical ApS

Jacobs and DeMott (2001) Laboratory Test Handbook, 5th edition, Lexi-Comp, Inc., Hudson, Ohio, p 21

Update:

7/14/2005: Added clarification on draw volume for repeat analysis.
4/22/2010: TAT update, previously listed as 1 hour, updated references



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