Changes in canine ionised calcium under three storage conditions.
OBJECTIVE
To determine the ionised calcium concentration following aerobic collection of blood and to compare ionised calcium concentration and pH of heparinised whole blood and plasma at 48 hours following collection under three different storage conditions to assess if ionised calcium concentration can be measured retrospectively.


METHODS
Blood was collected from 17 dogs for analysis of ionised calcium concentration and pH using a Rapidpoint 400 (Bayer) blood gas analyser. Blood was collected into a commercial preheparinised syringe and into a plain syringe, with subsequent transfer to a commercially available heparinised sample tube. Samples were analysed within 10 minutes, and the remainder was divided for storage. One aliquot was set-aside at room temperature for 48 hours, and the other was immediately centrifuged and the plasma divided for storage at room temperature and at 4 degrees C for 48 hours each. In all samples, ionised calcium concentration and pH were measured again at 48 hours after storage.


RESULTS
There was no significant difference in ionised calcium concentration or pH between anaerobically and aerobically collected heparinised whole blood analysed within 10 minutes of collection. At 48 hours, ionised calcium concentrations had decreased under all storage conditions irrespective of the direction of pH change.


CONCLUSIONS
Ionised calcium concentration can be measured in aerobically collected samples within 10 minutes and at 48 hours after collection under the conditions described.
Brennan
S F
SF
Department of Small Animal Clinical Studies, Faculty of Veterinary Medicine, University College Dublin, Belfield, Ireland.
O'donovan
J
J
Mooney
C T
CT
D000818:Animals; D001784:Blood Gas Analysis / Q000295:instrumentation / Q000662:veterinary*; D001793:Blood Preservation / Q000295:instrumentation / Q000662:veterinary*; D001800:Blood Specimen Collection / Q000662:veterinary*; D002118:Calcium / Q000097:blood*; D002245:Carbon Dioxide / Q000097:blood; D004285:Dogs / Q000097:blood*; D006863:Hydrogen-Ion Concentration; D012189:Retrospective Studies; D013594:Syringes; D013696:Temperature
D002245:Carbon Dioxide; D002118:Calcium