The spot test is not a reliable screening procedure for mucopolysaccharidoses.

Abstract

To check the reliability of the Ames MPS paper spot test, which is based on the Azure A dye, we sent a series of urine samples to three laboratories where the spot test is part of the metabolic screening for mucopolysaccharidoses. In these laboratories false-negative results ranged between 19% and 35% and false-positive results ranged between 12% and 29% of all samples submitted. In contrast, the quantitative dimethylmethylene blue test (Clin Chem 1989;35:1472-7) detected an increased glycosaminoglycan content in all urine samples from mucopolysaccharidosis patients and gave no false-positive results. In the latter procedure, glycosaminoglycan content is expressed per millimole of creatinine, and age-dependent reference values are used. We conclude that the Ames spot test and other spot tests are unreliable as a screening procedure for mucopolysaccharidoses and should not be used to screen for these diseases.

• Authors: J G de Jong, J J Hasselman, A A van Landeghem, H L Vader, R A Wevers
• Journal: Clinical chemistry (Clin Chem) Vol. 37 Issue 4 Pg. 572-5 (Apr 1991) ISSN: 0009-9147 [Print] England
• PMID: 1901775 (Publication Type: Journal Article)

Chemical References

• Azure Stains
• Glycosaminoglycans
• Reagent Strips
• Azure A
• Methylene Blue
• 1,9-dimethylmethylene blue

Topics

• Azure Stains
• False Negative Reactions
• False Positive Reactions
• Glycosaminoglycans (urine)
• Humans
• Methylene Blue
• Mucopolysaccharidoses (diagnosis, urine)
• Reagent Strips
• Reproducibility of Results