Strategy for determining racial and environmental similarities and differences for plasma proteins

The aim of this protocol is to establish a common basis for the production of reference values and well-defined and documented reference intervals for plasma proteins, based on common standardization, using the IFCC/BCR/CAP Certified Reference Material CRM 470. The strategy is to search for racial and environmental/geographical similarities and sources of differences in order to describe the main causes for variability among smaller or larger groups in selected societies and to estimate the sizes of differences for the different proteins according to the investigated sources. For this purpose, groups of reference individuals are selected according to race and geographical/environmental location, e.g. African Americans and Caucasians from the US. The reference individuals are groups of approximately 160 healthy male blood donors, 20 to 60 years of age. Rule-out criteria are positivity for HIV, hepatitis B and C antibodies and blood hemoglobin below the lower reference limit. Exclusion in relation to different C-reactive protein (CRP) levels will be investigated. Coagulation, storage conditions, transport, and the procedure for thawing are specified. The laboratories undertaking the measurements must have adequate analytical performance, and calibration and quality of performance are defined and documented, together with recommended control materials and procedures. Statistical models for describing distributions and for comparing groups are described. It is recommended that the data be presented as reference limits with 90% confidence intervals of those limits.