Update of a colorimetric method for quantitative determination of galactose in blood samples: A simple and rapid method for the early detection of inherited metabolic diseases

Abstract

Background: A colorimetric microassay for the quantitative determination of galactose in the blood was taken and updated. This method helps in diagnosis and follow-up of several inherited metabolic diseases connected to galactose metabolism deficiency such as galactosemia, glycogenosis, glycosylation, tyrosinemia and citrin deficiency. Galactose assay in the blood presents difficulties due to interference with glucose. In this study, we update a method to get around these difficulties.

Method: This procedure was based on the incubation of whole blood with orcinol in a strongly acidic solution to form a galactose and glucose complexes able to absorb at two different wavelengths.

Results: The standard curve analysis for the individual solutions of these two sugars showed a wide range of linearity from 0 to 200 mg / l. Under optimal experimental conditions, the stirring time of the orcinol is 3 minutes, the heating time of the reaction is 20 minutes at 56 ° C, and the duration of the incubation in the dark is 40 minutes. The analysis is carried out on fresh blood. The maximum absorbance of galactose and glucose is respectively 569 nm and 421 nm. An adapted diagnosis algorithm was developed based on our results.

Conclusion: this method could help in screening and identifying patients with hypergalactosemia that need further investigations. It could represent a promising method for neonatal screening in countries with limited resources.

Keywords: Colorimetric essay; Galactose; Inherited metabolic diseases; Metabolism; Orcinol.