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HelpTest Code Anion Gap Info Only Anion Gap
Useful For
This calculation is reported on all chemistry panels that contain electrolyte tests and cannot be ordered separately.
The Anion Gap calculation: Na - (CL + CO2) = Anion Gap (mmol/L).
Known causes of a low anion gap are bromide use (falsely high chloride) or viscosity effects (gives short sample).
High anion gaps are seen in acidotic states due to consumption of bicarbonate ion by organic acids leading to increased levels of unmeasured organic anions.
Synonyms/Keywords
Balance, Electrolyte
Specimen Requirements
| Fasting Required | Specimen Type | Preferred Container/Tube | Acceptable Container/Tube | Specimen Volume | Specimen Minimum Volume (allows for 1 repeat) |
Pediatric Minimum Volume (no repeat) |
|---|---|---|---|---|---|---|
| No | Serum/ Plasma | Red Top (RTT) Lithium-heparin Plasma Separator (PST) | Lithium or Sodium-heparin Green Top (GTT) Gold Top (GDTT) | 1 mL | 0.3 mL | 0.6 mL whole blood |
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum/Plasma | Refrigerate | 1 week |
| Frozen | >1 week |
Rejection Criteria
Samples collected with Potassium Oxalate/Sodium Fluoride
Test Components
Sodium, Chloride, Bicarbonate
Reference Range Information
| Performing Location | Reference Range |
|---|---|
| All Performing Sites | 2-16 mmol/L |
Marshfield Labs Performing Department
Marshfield Labs Chemistry
Performing Information
| Performing Location | Day(s) Test Performed | Analytical Time | Methodology/Instrumentation |
|---|---|---|---|
| Chippewa Falls | Monday through Friday | Less than 2 hours | Calculation: Na - (Cl +CO2) |
| Weston | Monday through Sunday | Less than 2 hours | Calculation: Na - (Cl +CO2) |
| Eau Claire | Monday through Sunday | Less than 2 hours | Calculation: Na - (Cl +CO2) |
| Park Falls | Monday through Sunday | Less than 2 hours | Calculation: Na - (Cl +CO2) |
| Ladysmith | Monday through Friday | Less than 2 hours | Calculation: Na - (Cl +CO2) |
| Rice Lake | Monday through Sunday | Less than 2 hours | Calculation: Na - (Cl +CO2) |
| Marshfield | Monday through Sunday | Less than 2 hours | Calculation: Na - (Cl +CO2) |
| Menomonie | Monday through Friday | Less than 2 hours | Calculation: Na - (Cl +CO2) |
| Minocqua | Monday through Sunday | Less than 2 hours | Calculation: Na - (Cl +CO2) |
| Stevens Point | Monday through Friday | Less than 2 hours | Calculation: Na - (Cl +CO2) |
| Wisconsin Rapids | Monday through Friday | Less than 2 hours | Calculation: Na - (Cl +CO2) |
Ordering Applications
This is a calculation reported on all chemistry panels that contain electrolyte tests and cannot be ordered separately. The Anion Gap calculation: Na - (CL + CO2) = Anion Gap (mmol/L).