Comments: |
The anion gap or electrolyte balance is calculated by the formula Na -
(Cl +HCO3). In normal individuals most of the anion gap is due to
protein. When an unmeasured anion such as ketones, lactate, formate, or
oxalate is present an elevated anion gap results. While the values for
the anion gap are method dependent, there is agreement that an anion
gap > 16 is considered elevated. The reasons for a decreased anion gap
are fewer and include low proteins, multiple myeloma (tend to be
positively charged) and bromide ingestion (falsely counted as
chloride). Patients may have a normal anion gap and still have
acidosis. This is known as hyperchloremic acidosis where an elevated
chloride compensates for the decreased bicarbonate. |
