|Values are valid only on day of printing.|
Centrifuged urine is mixed with a dimethylmethylene blue (DMB)/tris hydroxymethlyaminomethane (TRIS) solution. The metachromatic dye DMB binds with glycosaminoglycans (GAG) and the complex formed changes the spectra of the dye. The pink color complex is measured at 520 nm.(deJong JG, Wevers RA, Liebrand-van Sambeek R: Measuring urinary glycosaminoglycans in the presence of protein; an improved screening procedure for mucopolysaccharidoses based on dimethylmethylene blue. Clin Chem 1992;38:803-807; Panin G, Naia S, Dall'Amico R, et al: Simple spectrophotometric quantification of urinary excretion of glycosaminoglycan sulfates. Clin Chem 1986;32:2073-2076)
Liquid chromatography-tandem mass spectrometry (LC-MS/MS) (qualitative):
Chondroitin sulfate, dermatan sulfate, heparan sulfate, and keratan sulfate are determined by LC-MS/MS analysis. Urine specimens are evaporated and the dry residue is subjected to methanolysis yielding the mucopolysaccharides for analysis as their unique repeating disaccharide units. LC-MS/MS is performed using a short column (50 mm x 2.1 mm, 3 micron) to separate the mucopolysaccharides from the bulk of the specimen matrix. The mass spectrometer (MS/MS) is operated in the multiple reaction monitoring positive mode. (Auray-Blais C, Bherer P, Gagnon R, et al: Efficient analysis of urinary glycosaminoglycans by LC-MS/MS in mucopolysaccharidoses type I, II and VI. Mol Genet Metab 2011 Jan;102:49-56)
MPS, quantitative: Monday, Wednesday; 12 p.m.
MPS, qualitative: Set up Thursday, Result Friday