title: [Effect of reagent batch on activated partial thromboplastin time in canine plasma and use of the ratio system for standardization].
abstract: In order to test the variability of the results of the activated partial thromboplastin time (APTT) in different reagent batches, 40 samples (20 from healthy dogs, 15 from patients with prolonged APTT as a result of different congenital or acquired haemostasis disorders, 5 from healthy dogs after in vitro addition of heparin) were used to compare 6 different lot Nos. of two commercial APTT-reagents (Pathromtin, PTT Reagent). Although the Friedman test showed a reagent batch dependency (p < 0.0001) for both reagents, only minor quantitative differences were observed with a variation coefficient of 2.7% (Pathromtin) and 2.4% (PTT Reagent), respectively. A second experiment was based on 105 samples measured with two batches of a third reagent (APTT-FS) with remarkable differences of results. Convergence of the results was achieved by converting into ratio values (quotient measurement value/control). However, statistical comparison still showed a significant difference. The study shows the good reproducibility of the APTT measured with different batches of the reagents Pathromtin and PTT Reagent in canine plasma, indicating that standardization is unnecessary. A standardization based on the ratio system can be used for reagents with a low batch consistency, requiring a high-quality control.
authors.affiliation: Klinik für kleine Haustiere, Tierärztlichen Hochschule Hannover.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Mischke
mesh_terms: D000818:Animals; D001778:Blood Coagulation Disorders / Q000097:blood / Q000175:diagnosis / Q000662:veterinary*; D001780:Blood Coagulation Tests / Q000379:methods / Q000592:standards / Q000662:veterinary*; D002138:Calibration; D004283:Dog Diseases / Q000097:blood / Q000175:diagnosis*; D004285:Dogs / Q000097:blood*; D007202:Indicators and Reagents; D010314:Partial Thromboplastin Time / Q000662:veterinary*; D011517:Prothrombin Time / Q000662:veterinary; D011786:Quality Control; D011933:Reagent Kits, Diagnostic / Q000592:standards / Q000662:veterinary*; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D007202:Indicators and Reagents; D011933:Reagent Kits, Diagnostic
vernacular_title: Einfluss der Reagenzcharge auf die aktivierte partielle Thromboplastinzeit in caninem Plasma und Anwendung des Ratio-Systems zur Standardisierung.