[Great discrepancies between European, Dutch and Belgian criteria for the use of statins in the prevention of primary cardiovascular disease in family practice]. / Grote discrepanties tussen Europese, Nederlandse en Belgische criteria voor primaire cardiovasculaire preventie met statinen in de huisartsenpraktijk.

OBJECTIVE: To determine the differences in prescribing advice for statines in primary cardiovascular prevention, applying different protocols, in a first-line setting. METHOD: In February-March 2000, at the general practice 'Medicine for the People' in Deurne-Antwerp, Belgium, all contacts with patients known with at least one cardiovascular risk factor and no signs of cardiovascular disease were included in the study. The absolute risk of developing cardiovascular disease in the next 10 years was calculated per patient according to the protocols of the 'European Society of Cardiology' (ESC) and the Dutch College of General Practitioners (NHG) and it was determined whether these protocols advised prescription of statines. It was also determined if the Belgian criteria for repayment of statines, developed by the Rijksinstituut voor Ziekte- en Invaliditeitsverzekering (RIZIV) were met. RESULTS: The study group comprised 143 patients with a mean age of 66 years, of which 51 (36%) were men. According to the RIZIV criteria 75 (52%) patients of these 143 were eligible for the repayment of statines. The NHG protocol advised to prescribe statines for 4 (3%) patients and the ESC protocol for 69 (48%) patients. Of the 75 patients who were considered for repayment, 34 (45%) according to the ESC protocol and 74 (99%) according to the NHG protocol did not need statines. Also, in the whole study population, 28 (20%) patients needed statines according to ESC and 3 (2%) patients according to NHG, but they could not get repayment for statines according to the RIZIV. The ESC protocol estimated the risk per patient on average 8.5% (95% confidence interval: 7.1-9.8; p < 0.0001) higher than the NHG protocol. CONCLUSION: The NHG protocol estimated the risk significantly and markedly lower than the European protocol, although they are both based on the same Framingham data. There also existed a weak concordance between both protocols. The RIZIV criteria were not 'evidence-based'. They incited to an irrational and wasting prescribing behaviour. There is a need for an integrated guideline for primary cardiovascular prevention and for the adjustment of the RIZIV criteria.

Microplate washing: process description and improvements.

Heterogeneous immunoassays require wash steps in order to separate bound from free constituents. In this paper we demonstrate that in microplate assays the washing process includes two separate physical processes: (1) a rapid and wash volume-dependent direct dilution of the droplet-shaped residual volume, and (2) a diffusion-limited and strongly time-dependent dilution of a residual layer of liquid, which necessitates the use of time-consuming soak times in the immunoassay. We have shown that optimizing the motion of the wash fluid effectively reduces the residual layer thickness that results in extended soak times. This results not only in improved washing efficiency and reduced background variance in the immunoassay, it also yields a significantly improved immunoassay sensitivity.