Sources of Variability in Dose Response Platelet Aggregometry

Summary

An experiment designed to assess the components of variability of a number of measures of platelet aggregability showed that the ADP ED50 (the estimated dose of adenosine diphosphate at which primary aggregation occurs at half its maximum velocity) had the least method error of any of the parameters measured, but that none had a very high between-person component of variability. A simultaneous comparison of a syringe technique and a free-flowing technique for venepuncture revealed no differential effects on the aggregation parameters measured. An enforced increase in the stirring speed in the aggregometer led to an experiment which showed that such a change did not apparently affect the ED50s.

Keywords

Platelet aggregation - Dose response - Variability - Stirring speed

• References

• 1 Thompson SG, Vickers MV. Methods in dose response platelet aggregometry. Thromb Haemostas 1985; 53: 216
• 2 Born GV R. Aggregation of blood platelets by adenosine diphosphate and its reversal. Nature 1962; 194: 927-929
• 3 Triplett DA, Harms CS, Newhouse P, Clarke C. Platelet Function. Am Soc Clin Pathol. Chicago: 1978. pp 87-89
• 4 Coller BS, Gralnick HR. The effect of stir bar size and shape on quantitative platelet aggregation. Thromb Res 1976; 8: 121-129
• 5 Mustard JF, Packard MA. Factors influencing platelet function: Adhesion, release, and aggregation. Pharmacol Rev 1970; 22: 97-187
• 6 Baker RJ, Nelder JA. The GLIM system. Numerical Algorithms Group; Oxford: 1978
• 7 Huitson A. The analysis of variance: A basic course. Griffin London: 1970
• 8 Royston JP. An extension of Shapiro and Wilk’s W test for normality to large samples. Appl Statist 1982; 31: 115-124
• 9 Altman DG, Bland JM. Measurement in medicine: the analysis of method comparison studies. Statistician 1983; 32: 307-317
• 10 Altman DG. Statistics and ethics in medical research:III How large a sample. Br Med J 1980; 281: 1336-1338