ARIC Hemostasis Study - III. Ouality Control

Abstract

SummaryMethods and results from the quality assurance program of the Atherosclerosis Risk in Communities (ARIC) Study regarding hemostasis variables are presented, following up previous reports in this journal on standardized procedures for blood collection and processing (7) and an organized plan for the performance of those procedures (8). Efforts were made to control for and assess all sources of variability, from venipuncture to laboratory analysis, including also local field center processing and sample shipping. The quality control program included (a) a standardized protocol for blood collection and processing; (b) training, certification, and annual recertification of field center personnel for blood collection and processing; (c) monitoring of fasting times, phlebotomy times, processing times, and shipping problems; (d) hemostatic laboratory internal quality control; (e) a replicate blood sample program; (f) an intraindividual variability study; and (g) continual monitoring of quality control and study participants’ data. This paper focused on items (c), (d), and (e). Measures of Variation, generally Standard deviations and coefficients of Variation, are estimated for replicate blood sampling and internal quality control data, for activated partial thromboplastin time, fibrinogen, factor VII and VIII activity, von Willebrand factor, antithrombin-III, and protein C. The results demonstrate that it is possible to reliably measure these hemostatic variables in a large multicenter study.

Body size measures, hemostatic and inflammatory markers and risk of venous thrombosis: The Longitudinal Investigation of Thromboembolism Etiology

“…Blood was centrifuged at 4°C, and plasma frozen at −70°C until analysis in central laboratories. Baseline levels of fibrinogen, factor VII and VIII coagulant activity (FVIIc, FVIIIc), and were measured, and in ARIC only, the activated partial thromboplastin time (aPTT), protein C and von Willebrand factor were measured, as previously described[15, 16]. Both studies measured white blood count at laboratories near each field center.…”

Coagulation factors IX through XIII and the risk of future venous thrombosis: the Longitudinal Investigation of Thromboembolism Etiology

“…Baseline factor VIII coagulant activity (VIIIc) was measured by one-stage clotting assays during enrollment in all participants except the additional CHS black cohort. 19,20 In the nested case-control sample, factor IX, X, XI, XII, and XIIIA subunit antigenic levels were measured in citrate plasma by sandwich enzyme-linked immunoassays using reagents with affinity-purified polyclonal antibodies from Enzyme Research Laboratories. Assays were rarely done using post-VTE event blood samples.…”

Associations of the β-fibrinogen Hae III and factor XIII Val34Leu gene variants with venous thrombosis

“…The extension primer was 5′-TTCTATTTCAAAAGGGGC-3′. In ARIC, fibrinogen was measured in the entire cohort during enrollment by the Clauss method with reagents and calibration materials (Fibriquik) from General Diagnostics (Organon-Technika Co) [26]. In CHS, fibrinogen was measured in the entire cohort during enrollment by a modification of the Clauss method using a BBL Fibrometer (Becton Dickinson) [27].…”