Reducing error in feline platelet enumeration by addition of Iloprost to blood specimens: comparison to prostaglandin E1 and EDTA.
BACKGROUND
Prostaglandin E1 (PGE1) and Iloprost inhibit platelet aggregation and should prevent or minimize preanalytic error with feline platelet enumeration.


OBJECTIVE
The objective was to compare the relative effectiveness in reducing errors in platelet enumeration by adding Iloprost to feline EDTA blood specimens in comparison to adding PGE1 or EDTA alone. In addition, a grading system for platelet aggregation in blood smears was evaluated for effectiveness in predicting prominent errors and compared to ADVIA's PLT-CLM flag. Finally, the use of plateletcrit in feline blood with platelet aggregation was evaluated.


METHODS
Blood specimens from 35 cats were included. Blood was collected into EDTA tubes with or without Iloprost or PGE1, and was rapidly mixed. Platelet count (PLT), plateletcrit (PCT), mean platelet volume (MPV), and platelet flags were determined with an ADVIA 2120. Manual PLT was performed with a Leucoplate stain. PLT was determined by an IDEXX VetAutoread hematology analyzer (QBC).


RESULTS
Neither addition of Iloprost nor PGE1 to EDTA blood specimens completely prevented platelet aggregation. Iloprost-treated specimens had the least severe aggregation. PGE1 was better than EDTA alone. Significant errors in PLT results were consistently identified by the grading system. ADVIA's PLT-CL flag usually predicted significant errors in PLT. QBC PLT results showed high imprecision. Manual PLT error was smaller than ADVIA PLT in EDTA specimens with aggregation.


CONCLUSIONS
Adding Iloprost to feline blood specimens improved platelet enumeration accuracy. A grading system for severity of platelet aggregation and usually the ADVIA's PLT-CL alarm predicted specimens with significant errors in platelet enumeration.
Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Harold W
HW
Tvedten
Veterinary Student, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Kerstin
K
Bäcklund
University Animal Hospital, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Inger E
IE
Lilliehöök
D000527:Alprostadil / Q000494:pharmacology*; D000818:Animals; D001792:Blood Platelets / Q000166:cytology* / Q000187:drug effects*; D002415:Cats / Q000097:blood*; D004492:Edetic Acid / Q000494:pharmacology*; D016285:Iloprost / Q000494:pharmacology*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D010976:Platelet Count / Q000379:methods / Q000662:veterinary*
D010975:Platelet Aggregation Inhibitors; D004492:Edetic Acid; D000527:Alprostadil; D016285:Iloprost
Cat; QBC; platelet aggregation; plateletcrit; preanalytic error; thrombocyte count