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HelpTest Code CO2 Bicarbonate
Laboratory Code
LAB55
Specimen Requirements
Submit only one of the following:
Preferred
Specimen Type: Serum
Container/Tube: Gold Top (SSTII)
Volume: 5.0 mL
Minimum Volume: 0.5 mL serum
Collection Instructions: Allow specimen to clot for 30 mins and centrifuge within 2 hrs.
Acceptable
Specimen Type: Plasma
Container/Tube: Green Top (Li Heparin/PST)
Volume: 4.5 mL
Minimum Volume: 0.5 mL plasma
Collection Instructions: Centrifuge within 2 hrs
Specimen Stability
| Specimen Type | Serum/Plasma |
|---|---|
| Ambient | 1 day |
| Refrigerate | 7 days |
| Frozen | 2 weeks |
Send in primary tube, do not aliquot. A consequent decrease in the CO2 value of up to 6 mEq/L
can occur in the course of an hour once the specimen has been exposed to ambient air.
Methodology
Enzymatic Assay
Days and Times Performed
24 hrs, TAT 1 day
Specimen Condition
| Haemolysis | OK |
|---|---|
| Icterus | OK |
| Lipaemia | OK |
| Others | Not applicable |
Reference Interval
| Age | (mmo/L) |
|---|---|
| 0 – < 1 wk | 15 – 28 |
| 1 wk – 1 yr | 16 – 29 |
| 2 yrs – 9 yrs | 17 – 30 |
| 10 yrs – 17 yrs | 20 – 32 |
| ≥ 18 yrs | 22 – 32 |
Testing Laboratory
National University Hospital
Clinical Chemistry, 67724346
Useful For
Evaluation of acid-base status.
Service Code
31114
LOINC Code Information
2028-9
Alias
HCO3
Carbon Dioxide (CO2)
Update
Last updated 10/03/2025