Comparison of different anticoagulant associations on haemostasis and biochemical analyses in feline blood specimens.

Objectives Universal anticoagulant could be an alternative to the multiple blood sampling required for clinical pathology investigations in cats. An association of citrate, theophylline, adenosine and dipyridamole (CTAD) has been reported to be a good substitute for EDTA for haematology analysis in cats, limiting platelet clumping, and has also been shown to be valid for haematology, secondary haemostasis and some biochemical variables in humans. The aim of the study was therefore to investigate the effects of CTAD on in vitro platelet aggregation and compare results of secondary haemostasis and biochemistry tests, excluding a priori those variables not reliably measured in CTAD, such as sodium, chloride and divalent cations, in feline blood specimens collected in CTAD and paired citrate and heparin tubes. Methods Thirty blood specimens sampled in citrate and CTAD were analysed for in vitro platelet aggregation, and 60 blood specimens sampled in citrate or heparin and CTAD were analysed for plasma coagulation and a biochemistry panel. Results In vitro platelet aggregation was inhibited in CTAD compared with citrate specimens. Prothrombin time, activated partial thromboplastin time, antithrombin and fibrinogen results were similar, despite some significant differences. Measurements of triglycerides, cholesterol, glucose, urea, creatinine, phosphate, total proteins and alanine aminotransferase activity were similar and well correlated in CTAD and heparin plasmas, despite some significant differences and moderate biases. Albumin showed a marked positive proportional bias, and creatine kinase and alkaline phosphatase activities a moderate and marked negative mixed bias, respectively, but could be measured in CTAD if new reference intervals were calculated. Aspartate aminotransferase activity showed a marked negative proportional bias, along with a poor correlation and some clinical misclassifications just like the potassium concentration, and thus cannot be recommended to be measured in CTAD specimens. Conclusions and relevance In cats, CTAD cannot be used for primary haemostasis investigation but could be a suitable (almost) universal anticoagulant for routine haematology, as well as for plasma coagulation and many biochemistry variables.

Hematologic and Biochemical Biologic Variation in Laboratory Cats.

The biologic variation associated with a clinical pathology result is important to consider before reference intervals (RI) are used. Most available RI are population-based RI, in which the analytical variability, interindividual variability, and intraindividual variability are confounded. In addition, when the intraindividual variability is considerably less than the interindividual variability, a population-based RI is insufficiently sensitive to detect changes in a subject over time. Here we determined the biologic variation and reference change value (RCV) of hematologic and biochemical variables in laboratory cats. Blood specimens from 14 (7 females and 7 males) overnight-fasted laboratory cats sampled 7 times (days 1, 2, 7, 14, 31, 42, and 100) were analyzed regarding hematology and biochemistry variables. For each variable, analytical, intraindividual, and interindividual coefficients of variation were estimated prior to calculation of the index of individuality and the RCV. RBC variables (count, Hgb, Hct, MCV, MCH, MCHC, and RBC distribution width) and 5 biochemical analytes (cholesterol, creatinine, triglycerides, ALP, and calcium) exhibited marked individuality, therefore indicating that subject-based reference intervals or RCV would be preferable when monitoring these variables in laboratory cats. Population-based RI were shown to be adequate for glucose and sodium, and both types of population and individual RI were similarly efficient for albumin, total protein, urea, ALT, AST, creatine kinase, chloride, carbon dioxide, iron, magnesium, inorganic phosphate, and potassium and reticulocyte, WBC, neutrophil, lymphocyte, monocyte, eosinophil, and platelet counts. The RCV determined in the present study provide a valuable tool for monitoring hematologic and biochemical variables in healthy laboratory cats.