title: Laboratory methods and quality assurance in the Cardiovascular Health Study.
abstract: The Cardiovascular Health Study is an observational cohort study of risk factors for cardiovascular disease in 5201 participants, ages > or = 65 years. We report the methods and quality-assurance results for blood procurement, processing, shipping, storage, and sample analysis used during the first examination period (May 1989-June 1990). The most frequent difficulty in phlebotomy and processing was the requirement of more than one venipuncture (in 2.6% of the participants). The CVs for control materials ranged from 0.93% for glucose to 10.7% for insulin; most were < 4%. In addition to standard quality-assurance methods, we applied two other methods: technical error calculation for replicates, and weighted linear regression to assess time trend in results of control materials. After outliers were excluded, technical error values ranged from 1.7 for uric acid to 18.8 for insulin. Factor VII and factor VIII had slight trends over the 12-month analysis period. Results of quality-assurance analyses used to resolve problems were successful, thereby improving the second laboratory examination.
authors.affiliation: Department of Pathology, University of Vermont College of Medicine, Burlington 05401.
authors.forename: M
authors.initials: M
authors.lastname: Cushman
authors.forename: E S
authors.initials: ES
authors.lastname: Cornell
authors.forename: P R
authors.initials: PR
authors.lastname: Howard
authors.forename: E G
authors.initials: EG
authors.lastname: Bovill
authors.forename: R P
authors.initials: RP
authors.lastname: Tracy
mesh_terms: D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D001800:Blood Specimen Collection / Q000379:methods; D002318:Cardiovascular Diseases / Q000097:blood*; D002624:Chemistry, Clinical / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D005167:Factor VII / Q000032:analysis; D005169:Factor VIII / Q000032:analysis; D005340:Fibrinogen / Q000032:analysis; D006801:Humans; D007328:Insulin / Q000097:blood; D011786:Quality Control; D012044:Regression Analysis; D014280:Triglycerides / Q000097:blood
chemical_list: D001786:Blood Glucose; D007328:Insulin; D014280:Triglycerides; D005167:Factor VII; D005169:Factor VIII; D005340:Fibrinogen