Chloroquine minimizes sampling artefacts for radioimmunological determination of thromboxane B2 in plasma

Chloroquine is known to inhibit platelet activation by various mechanisms including arachidonic acid liberation from membrane phospholipids. We therefore examined the influence of chloroquine in addition to the conventional EDTA/acetylsalicylic acid cocktail on thromboxane B2-plasma values. In 11 healthy volunteers the influence of venous occlusion, needle diameter and EDTA (+ acetylsalicylic acid + chloroquine) was examined. In 27 healthy adults, 51 patients with clinically manifested coronary heart disease as well as in 31 patients with peripheral vascular disease parallel samples drawn in the presence of chloroquine showed lower thromboxane B2 in all these three groups of patients, especially in conditions associated with platelet activation and high thromboxane B2-values. These findings suggest that the routine addition of 10 mM chloroquine to the conventional stabilization cocktail can strongly be recommended.