Determination of strong ion gap in healthy dogs.
OBJECTIVE
To determine and compare reference intervals of the strong ion gap (SIG) in a group of healthy dogs determined with 2 different equations.


METHODS
Prospective observational study.


METHODS
Tertiary referral and teaching hospital.


METHODS
Fifty-four healthy dogs.


METHODS
None.


METHODS
Serum biochemistry and blood gas analyses were performed for each dog. From these values, SIG was calculated using 2 different equations: SIG(1) = SID(a) {[Na (+)] + [K(+)] - [Cl(-)]+ [2 × Ca(2+)] + [2 × Mg(2+)] - [L-lactate]}- SID(e) {TCO(2) + A(-)} and SIG(2) = [albumin] × 4.9-anion gap. Reference intervals were established for each SIG equation using the mean ± 1.96 × standard deviation (SD).


RESULTS
For SIG(1), the median was 7.13 mEq/L (range, 1.05-11.30 mEq/L) and the derived reference interval was 1.85-10.61 mEq/L. Median SIG(2) was -0.22 mEq/L (range, -5.34-6.61 mEq/L) and the mean SIG(2) was -0.09 mEq/L (95% confidence interval for the mean, -0.82-0.65 mEq/L). The derived reference interval was -5.36-5.18 mEq/L. The results of the SIG calculations were significantly different (P < 0.0001) between the 2 equations used.


CONCLUSIONS
The 2 equations used to calculate SIG yielded significantly different results and cannot be used interchangeably. The authors believe SIG(2) to be a more accurate reflection of acid-base status in healthy dogs, and recommend that this calculation be used for future studies.
Oradell Animal Hospital, Paramus, NJ 07652, USA. Astivet2@optonline.net
Pamela K
PK
Fettig
Dennis B
DB
Bailey
Kristi M
KM
Gannon
D000136:Acid-Base Equilibrium / Q000502:physiology*; D000818:Animals; D001774:Blood Chemical Analysis / Q000662:veterinary; D004285:Dogs / Q000097:blood / Q000502:physiology*; D004573:Electrolytes / Q000097:blood*
D004573:Electrolytes