N-acetylneuraminic acid estimation in human serum by neuraminidase and resorcinol/ferric(III) chloride reagent in hydrochloric solution.

By the method described the serum concentration of the protein-bound or the total N-acetylneuraminic acid can be determined. The estimation of the protein-bound N-acetylneuraminic acid is a specific method. In comparison to the Arzneibuch (D.L.) GDR-method (Vol. 2, Akademie Verlag Berlin, 1985) based on Svennerholm (Biochim. Biophys. Acta 24 (1957) 604-611) the advantages of our estimation are: high stability of the dye complex during a period of at least one hour for a final concentration of at least 6.0 mol/l hydrochloric acid; omission of the time-consuming resuspension of the protein precipitation and the extraction of the dye product with n-amyl alcohol; and the lack of diminution of the monosaccharide influence.