title: Determination of Biological Variance and Validation of a Fluorometric Assay for Measurement of α-l-Iduronidase Activity in Dried Blood Spots Samples: The First Experience in Iran.
abstract: Methods for assaying lysosomal diseases in dried blood samples are very useful today due to its several advantages related to the stability of samples, its transportation, handled and analysis, and its potential use for newborn screening compared to traditional methods in leucocytes samples. For this reason, it is important to validate these assays before being used in routine laboratory. Because of different in biological markers based on ethnicity, we aimed this study to validation a DBS-based fluorometric assay for measurement of α-l-Iduronidase activity for diagnosis of MPS I patients in Iran. DBS samples were collected from 15 MPS I patients and 60 healthy age matched subjects. Diagnostic value, biological variance and α-l-Iduronidase activity were determined. DBS α-l-Iduronidase activity was significantly higher in male subjects than in female group. Using a cut-off level of 1.08 µmol/spot 20 h, sensitivity and specificity were 100 and 98 %. The linearity of test was proved and we showed that within-run and between run precision were 5.6 and 14.66 %. Measurement of α-l-Iduronidase activity in DBS samples is an accurate test for diagnosis of MPS I and because of its rapid shipping and simplicity to keeping, DBS-based enzyme activity could be considered as a useful diagnostic tool in this disease.
authors.affiliation: Department of Clinical Biochemistry, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Abdi
authors.affiliation: Department of Biochemistry and Nutrition, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: Mohammad Said
authors.initials: MS
authors.lastname: Hakhamaneshi
authors.affiliation: Department of Pediatric, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Alaei
authors.affiliation: Department of Epidemiology and Biostatistics, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: Namam-Ali
authors.initials: NA
authors.lastname: Azadi
authors.affiliation: Department of Pediatrics, Imam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Rahim
authors.initials: R
authors.lastname: Vakili
authors.affiliation: Department of Pediatric, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: Daniel
authors.initials: D
authors.lastname: Zamanfar
authors.affiliation: Department of Clinical Biochemistry, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Taghikhani
authors.affiliation: Department of Biochemistry, Pasteur Institute of Iran, Pasteur Square, Pasteur Street, Tehran, Iran.
authors.forename: Shohreh
authors.initials: S
authors.lastname: Khatami
keywords: Dried blood spot; Fluorometric test; Iran; Mucopolysaccharidosis type I; Validation; α-l-Iduronidase activity