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Test Code LAB55 CO2 Total (Bicarbonate), Blood

Performing Laboratory

St. Louis Children's Hospital Laboratory - Chemistry

Specimen Requirements

Note: This test is also available as part of LAB17, Comprehensive Metabolic Panel (CMP); LAB15, Basic Metabolic Panel; LAB16, Electrolyte (Lytes) Panel; and LAB19 Renal Function Panel. See Common Panel Test Combinations to avoid duplicate requests if needed.

 

Patient Preparation: None

Collection Container/Tube:

Preferred: Mint green-top lithium heparin (MNTGRN LiHep) tube

Acceptable: Green samplette/microtainer, plain red-top tube, or Gold SST gel tube

Specimen Collection Volume: 1.0 mL (minimum 0.6 mL)

Submission Container/Tube: If specimen is coming from outside facility and collected in a microtainer or plain red-top tube, aliquot processed sample into a plastic vial for transport (labeling with specimen type).

Special Instructions: None

 

Sample Rejection

Mislabled or unlabeled specimens

Logistics

Test Availability: Monday-Sunday

Cut-off time: None, performed as received

Turnaround Time: Same Day; 2 hours from receipt in performing lab

Reference Values

Reference Interval: 

<18 years: 20-30 mmol/L                                            
≥18 years: 22-32 mmol/L                                                             

Critical Value: <10 mmol/L    (all ages)

Critical test results will be called back automatically initially and every 24 hours thereafter.

 

Methodology

Enzymatic Endpoint (Phosphoenolpyruvate Carboxylase [PEPC])

Limitations

  • In very rare cased gammopathy, in particular type IgM (Waldenstrom's macroglobulinemia), may cause unreliable results.

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processing Instructions: Centrifuge to separate within 4 hours of collection. If specimen is collected in microtainer or plain red-top tubealiquot sample into a Roche false-bottom tube for testing (labeling aliquot with specimen type).

Processed Volume: 0.3 mL plasma/serum

Analyte Stability:

Specimen Type Temperature Time
Whole Blood (unprocessed) Ambient 1 hour
Plasma/Serum (processed) Refrigerated (preferred)                 1 hour
  Ambient  1 hour                                  
  Frozen  NA                                       
NOTE: Specimen is only stable 1 hour once cap of tube has been removed/vaccuum broken (or if shared specimen collected in syringe and spun down)

 

 

Test Classification and CPT Code

82374

LOINC

1962-0

Last Reviewed

06/2025