Plasma S-100b protein concentration in healthy adults is age- and sex-independent.

Thus, sodium citrateand EDTA-treated samples may yield more accurate values for cystine. In summary, the anticoagulant used in sample preparation may markedly affect the results of amino acid analysis by automated ion exchange chromatography. Sample preparation should be standardized, and clinicians should be aware of the possible sources of error. We recommend the use of either heparin or EDTA exclusively, with careful attention to potential inaccuracies in cystine concentrations with the former and PTEN with the latter.