Evaluation of thrombelastographic platelet-mapping in healthy cats
- Dr. Wood, an editor of the journal, was not involved in the peer-review process or in the decision to publish this article.
S.L. Blois, Department of Clinical Studies, Ontario Veterinary College, University of Guelph, 50 Stone Road, Guelph, Ontario N1G 2W1, Canada
Thrombelastography (TEG) permits analysis of clot formation but it is not specific for platelet activity. TEG PlateletMapping (TEG-PM) is a modification of TEG that uses adenosine diphosphate (ADP) and arachidonic acid (AA) as platelet agonists to define the contribution of platelets to clot formation.
The objectives of this study were to determine values for TEG-PM in healthy cats and the interassay variation of TEG-PM.
TEG-PM analysis was performed on blood specimens collected from 12 healthy cats and was repeated using a second blood specimen collected 2 hours later. Maximum amplitudes generated by thrombin (MAthrombin), fibrin (MAfibrin), ADP-stimulated platelet activity (MAADP), and AA-stimulated platelet activity (MAAA) were recorded.
Mean ± SD for MAthrombin was 51.1 ± 8.5 mm, for MAfibrin was 32.3 ± 17.7 mm, for MAADP was 32.3 ± 15.0 mm, and for MAAA was 24.5 ± 12.2 mm. Mean MAADP and MAfibrin were not significantly different, whereas mean MAAA was significantly lower than mean MAfibrin. Results from the first and second specimens were not significantly different. Correlation between the first and second specimens was moderate for MAthrombin, MAfibrin, and MAADP, but was poor for MAAA. A high degree of variability (coefficient of variation 47.7–60.0%) was observed for MAfibrin, MAADP, and MAAA.
As MAADP and MAAAAA were the same as or lower than MAfibrin, a valid baseline to determine platelet-stimulated clot formation could not be established. Considerable interassay variation and wide intervals for MAfibrin, MAADP, and MAAA values in this study indicate that TEG-PM should be used cautiously in feline patients. Several preanalytical factors should be examined in further detail.