Days Set Up
Daily, 24 hours
Analytic Time

Refer to handbook entry for Electrolyte Panel (LYTES), Renal Function Panel (RENAL), Basic Metabolic Panel (BASIC) or Comprehensive Panel (COMP)

MiChart Code
Anion Gap
Soft Order Code
AGAP

Test Updated:

Synonyms
 

Looking to order a test?

We’ve provided helpful links to make ordering easy.

Find a Requisition

All specimens should be accompanied by a requisition.

Submitting Specimens

Learn about how to properly label and where to ship specimens.

Order Kits and Supplies

MLabs provides all the supplies necessary for the collection of specimens.

Test FAQ

Visit our provider FAQ and learn about common questions to ordering tests.

Test Overview

Test Methodology

Anion Gap is calculated using the sodium, chloride and CO2 results on serum. The formula for calculating the anion gap is: Sodium - (Chloride + CO2) = Anion Gap
See the Sodium, Chloride and CO2 individual tests.

Test Usage

Anion Gap is automatically performed with the following panel tests: Electrolyte Panel (LYTES), Renal Function Panel (RENAL), Basic Metabolic Panel (BASIC) and/or Comprehensive Panel (COMP). It is not available as an individual test. Anion Gap is a calculated test using the sodium, chloride and CO2 results on serum. The formula for calculating is: Sodium - (Chloride + CO2) = Anion Gap

The primary clinical use of the anion gap is to assess acid-base disturbances in patients, particularly metabolic acidosis. A marked increase in anion gap (>25 mmol/L) is almost always evidence of metabolic acidosis. Increased anion gap results can be caused by renal failure, diabetic ketoacidosis, starvation, lactic acidosis, ethylene glycol intoxication and methanol intoxication. Reduced anion gap results are less common. Low anion gap can be associated with hypoalbuminemia, myeloma, and lithium intoxication. Laboratory error in measurement of any of the three components of the calculation (Sodium, chloride or CO2) can invalidate the anion gap result.

Reference Range

4 - 12 mmol/L

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Onsite

Refer to handbook entry for Electrolyte Panel (LYTES), Renal Function Panel (RENAL), Basic Metabolic Panel (BASIC) or Comprehensive Panel (COMP)

Collection Offsite

Refer to handbook entry for Electrolyte Panel (LYTES), Renal Function Panel (RENAL), Basic Metabolic Panel (BASIC) or Comprehensive Panel (COMP)

Yellow Top Tube
Normal Volume
Refer to handbook entry for Electrolyte Panel (LYTES), Renal Function Panel (RENAL), Basic Metabolic Panel (BASIC) or Comprehensive Panel (COMP)
Minimum Volume
Refer to handbook entry for Electrolyte Panel (LYTES), Renal Function Panel (RENAL), Basic Metabolic Panel (BASIC) or Comprehensive Panel (COMP)

Billing Information

CPT Code
 
Pro Fee Code
 
LOINC
 

Have More Questions?

Explore our helpful billing resources:

Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.