UCSF Navigation Bar

UCSF Departments of Pathology & Laboratory Medicine Home Page

Lab Manual for UCSF Clinical Laboratories

Lab Manual for SFGH

Internal Resources

Click here for more information about laboratory operations and procedures

If you have additional questions regarding this test, please call: 415-353-1667

Search Our Test Menu

Carbon Dioxide, Total

Item Value
Approval req'd? No
Available Stat? Yes
Test code CO2AN
Performed by Parnassus & Mt. Zion Chemistry
In House Availability Test available 24 hours per day 7 days per week
Method pH electrode, using bicarbonate and sample CO2
Container type Gold top or Light Green top
Amount to Collect 1 mL blood Click here for Microdetermination info
Sample type Serum or plasma
Preferred volume 0.5 mL serum or plasma
Min. Volume 0.2 mL serum or plasma Click here for Microdetermination info
Units mmol/L
Normal range
0 - 15 years 16 – 30 mmol/L
≥ 16 years 22 – 32 mmol/L


1. Normal range for 0 to 15 year old children adapted from Beckman Coulter's "Pediatric Reference Range Guidelines for Synchron Systems" Bulletin 9345
2. Normal range for >18y adults was determined by testing 271 male and female healthy blood donors at UCSF. Adult range adapted for children 16-18 years
Critical value < 15 mmol/L or > 40 mmol/L
Synonyms CO2; Anion gap
Stability Room temperature 8 hours, refrigerated 2 days, frozen at -20C 1 week
Turn around times STAT 1 hour, Routine 4 hours
Additional information The anion gap is calculated from the serum Sodium, Chloride and Total CO2 values using the equation: Na-(CL+CO2). The calculation is automatic whenever all three of the electrolytes are ordered together. It is not a separately orderable test. Normal range for the Anion Gap is 4-14.
LOINC code 2028-9
Last Updated 6/11/2014 11:41:44 AM
Entry Number 167
Lab Procedure Link Click here for Procedure
UCSF home page UCSF home page About UCSF Search UCSF UCSF Medical Center