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HelpTest Code HCO3 Bicarbonate, Serum
Reporting Name
Bicarbonate, SUseful For
Diagnosis and treatment of acid-base imbalance in respiratory and metabolic systems
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumNecessary Information
Patient's age and sex are required.
Specimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions:
1. Serum gel tube must be centrifuged within 2 hours of collection.
2. Red-top tube must be centrifuged, and the serum aliquoted into a plastic vial within 2 hours of collection.
Specimen Minimum Volume
0.25 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated | 24 hours |
Reference Values
Males
12-24 months: 17-25 mmol/L
3 years: 18-26 mmol/L
4-5 years: 19-27 mmol/L
6-7 years: 20-28 mmol/L
8-17 years: 21-29 mmol/L
≥18 years: 22-29 mmol/L
Females
1-3 years: 18-25 mmol/L
4-5 years: 19-26 mmol/L
6-7 years: 20-27 mmol/L
8-9 years: 21-28 mmol/L
≥10 years: 22-29 mmol/L
Reference values have not been established for patients that are <12 months of age.
Day(s) Performed
Monday through Sunday
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
82374
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| HCO3 | Bicarbonate, S | 1963-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| HCO3 | Bicarbonate, S | 1963-8 |
Clinical Information
Bicarbonate is the second largest fraction of the anions in plasma. Included in this fraction are the bicarbonate (HCO3[-]) and carbonate (CO3[-2]) ions, carbon dioxide in physical solution, as well as the carbamino compounds. At the physiological pH of blood, the concentration of carbonate is 1/1000 that of bicarbonate. The carbamino compounds are also present in such low quantities that they are generally not mentioned specifically.
The bicarbonate content of serum or plasma is a significant indicator of electrolyte dispersion and anion deficit. Together with pH determination, bicarbonate measurements are used in the diagnosis and treatment of numerous potentially serious disorders associated with acid-base imbalance in the respiratory and metabolic systems. Some of these conditions are diarrhea, renal tubular acidosis, carbonic anhydrase inhibitors, hyperkalemic acidosis, renal failure, and ketoacidosis.
Interpretation
Alterations of bicarbonate (HCO3) and carbon dioxide (CO2) dissolved in plasma are characteristic of acid-base imbalance. The nature of the imbalance cannot, however, be inferred from the bicarbonate value itself, and the determination of bicarbonate is rarely ordered alone. Its value has significance in the context of other electrolytes determined with it and in screening for electrolyte imbalance.
Cautions
Because the determination of bicarbonate (HCO3) actually includes dissolved carbon dioxide (CO2), this fraction will escape from the specimen into the air once the stopper is removed from the vacutainer tube. The rate of change in the bicarbonate determination is approximately 6 mmol/L in the course of 1 hour. If the logistics in the lab are different for processing high-volume routine specimens from STAT specimens, the extent of the error is bicarbonate determinations will be different. This is due to the length of time between removal of the stopper and sampling of the specimen for analysis. Fortunately, the errors in either case are relatively small and of little concern clinically.
Report Available
Same day/1 to 2 daysReject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
Method Name
Photometric/Enzymatic
Forms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.