title: Optimization of enzymatic diagnosis for mucopolysaccharidosis I in dried blood spots on filter paper.
abstract: OBJECTIVE
  The aim of this study was to validate an ultramicroassay with a reduced interference of hemoglobin for the enzymatic diagnosis of mucopolysaccharidosis I in dried blood spots on filter paper.
  
  
  METHODS
  A matrix of dried blood was incorporated within the calibration system. In addition, trichloroacetic acid was added to precipitate hemoglobin. Linearity, precision, accuracy and limits of detection and quantification were determined and α-l-iduronidase activity was obtained from 6 patients, 9 heterozygotes, 25 healthy adults and 500 neonates.
  
  
  RESULTS
  The ultramicroassay was linear, precise (coefficients of variation less than 10%) and accurate (recovery between 91 and 98%). The interference of hemoglobin was decreased within the hematocrit range of clinical interest: 35-55%.
  
  
  CONCLUSIONS
  This ultramicroassay increases in 2.5 times the difference between healthy individuals and patients with respect to the reference assay; optimizing enzymatic quantification and confirmatory biochemical diagnosis for mucopolysaccharidosis I.
authors.affiliation: Department of Biochemical Genetics, National Center of Medical Genetics, 146 Street No. 3102, Havana, Cuba. derbisch@cngen.sld.cu
authors.forename: Derbis
authors.initials: D
authors.lastname: Campos
authors.forename: Madelyn
authors.initials: M
authors.lastname: Monaga
authors.forename: Ernesto C
authors.initials: EC
authors.lastname: González
authors.forename: Darlenis
authors.initials: D
authors.lastname: Herrera
authors.forename: Daniurys
authors.initials: D
authors.lastname: de la Peña
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002138:Calibration; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D059788:Dried Blood Spot Testing / Q000592:standards*; D057075:Enzyme Assays / Q000592:standards; D006801:Humans; D007068:Iduronidase / Q000097:blood*; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D008059:Mucopolysaccharidosis I / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology; D010209:Paper; D012015:Reference Standards; D055815:Young Adult
chemical_list: D007068:Iduronidase