Malondialdehyde formation by blood platelets: a diagnostic test to assess acetylsalicylic acid induced thrombocytopathy?

We investigated whether the measurement of N-ethylmaleimide stimulated malondialdehyde (MDA) formation by blood platelets from normal subjects is equally sensitive to acetylsalicylic acid intake as are platelet aggregation studies. MDA production and platelet aggregation by collagen and arachidonate were assayed in ten healthy volunteers before and up to ten days after a single oral dose of 500 mg aspirin. Discordant results of the two tests were seen in several subjects 4 to 6 days after aspirin intake. In three cases with still suppressed MDA values on day 4, collagen or arachidonate induced aggregation was normalized. However, on day 6, when MDA was normalized in all subjects, the aggregation response to arachidonate was still pathologic in 5 of the ten volunteers. In case of a patient with abnormal aggregation response to arachidonate and/or collagen, therefore, a normal MDA value does not permit to exclude aspirin as the cause of the platelet dysfunction.