Name: Anion Gap
Test Name: Anion Gap
Health Link Test Code: LYTE
LIS Test Code: LYTS
CPT Code(s): See Electrolytes Panel
Included In: Electrolytes panel, Basic Metabolic Panel (BMP) and Comprehensive Metabolic Panel (CMP)
Methodology: Ion Selective Electrode and/or Enzymatic
Days Performed: Daily, 24 hours.
In-Lab Turnaround Time: 4 hours.
Stat In-Lab Turnaround Time: 1 hour.
Collection Container: Green cap with yellow ring (PST)
Also Acceptable: Green top, Red cap with yellow ring (SST), Red top
Tube must be at least one quarter full.
Collection Volume: 1 mL
Pediatric Collection Volume: 0.5 mL
Sample Analyzed: Plasma or serum
Testing Volume: 0.5 mL
Pediatric Testing Volume: 0.2 mL
Centrifuge. If a complete barrier has not formed, transfer cell-free plasma/serum to plastic vial. Tube must be at least one quarter full. Refrigerate specimen.
Transport specimen to the laboratory. Transport with coolant pack if coming from clinic location.
0 days and up: 7-14 mmol/L
Interpretation Type: Reference Interval
The anion gap is calculated by subtracting the sum of the chloride and total carbon dioxide from the sodium result.