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Bicarbonate
Abbreviation: HCO3
Panel: Metabolic, Kidney & Electrolytes · All metabolic & kidney tests
Typical adult reference range
| Conventional units | 23–30 mEq/L |
| SI units | 23–30 mmol/L |
Ranges vary between laboratories and methods — compare your result with the range printed on your own report.
What a high or low result can mean
High bicarbonate: high values can be seen in metabolic alkalosis and compensation for chronic respiratory acidosis.
Low bicarbonate: low values may occur in metabolic acidosis, including kidney and gastrointestinal causes.
These are associations, not a diagnosis: the same result can have several causes, and your clinician interprets it with the rest of your results and history.
Good to know
Reported as total CO2 on most chemistry panels.
◆ Kidney note
This test is closely tied to kidney health, and it is one a kidney specialist (nephrologist) watches closely. On this site, kidney-related results are a special focus: see the kidney and dialysis medicines in our Drug Guide and the kidney condition hubs for the wider picture.