Effect of sample collection, temperature and time of storage on β-galactosidase and total hexosaminidase activities in dried blood collected on filter paper

• Published in: Clinical chemistry and laboratory medicine Vol. 49; no. 8; pp. 1299 - 1302
• Main Authors: de Castilhos, Cristina D., Mezzalira, Jamila, Goldim, Mariana P.S., Werlang, Frederico G., Coelho, Janice C.
• Format: Journal Article
• Language: English
• Published: Berlin Walter de Gruyter 01.08.2011; De Gruyter
• Subjects: 4-methylumbelliferyl fluorescent assay; beta-Galactosidase - blood; beta-Galactosidase - metabolism; beta-N-Acetylhexosaminidases - blood; beta-N-Acetylhexosaminidases - metabolism; Biological and medical sciences; Blood Specimen Collection - instrumentation; Blood Specimen Collection - methods; dried blood spots on filter paper; General aspects; Humans; inborn errors of metabolism; Investigative techniques, diagnostic techniques (general aspects); lysosomal enzymes; Lysosomal Storage Diseases - blood; Lysosomal Storage Diseases - enzymology; Medical sciences; Temperature; Time Factors; Temperature; Enzyme; Conservation; Lysosome; Samplings; β-N-Acetylhexosaminidase; Fluorescence; Metabolic diseases; Filter paper; 4-methylumbelliferyl fluorescent assay; inborn errors of metabolism; lysosomal enzymes; Enzymopathy; Congenital disease; Biological activity; Blood; Glycosylases; Assay; Storage; Glycosidases; dried blood spots on filter paper; Clinical biology; Hydrolases; Blood trace; β-Galactosidase
• ISSN: 1434-6621; 1437-4331
• DOI: 10.1515/CCLM.2011.193

Background: Dried blood spots (DBS) on filter paper is a valuable sampling technique in clinical chemistry, but the stability of enzymes used in the diagnosis of lysosomal storage diseases (LSDs) needs to be evaluated. Methods: In a first experiment, blood from 20 subjects was collected using a syringe without additives and distributed into EDTA tubes, heparin tubes, and spotted on filter paper for the comparison of sampling effects. In a second experiment, blood from 30 healthy subjects was spotted on filter paper and analyzed for β-galactosidase and total hexosaminidase activities after storage of the samples at different temperatures for up to 180 days. Results: Initially, we observed that enzyme activities were the same, independent of the collection method. When DBS was stored at 37°C the activity of β-galactosidase dropped to 85% of the initial value after 180 days (p<0.05). At all other temperatures (–20°C, 4°C and 25°C), the results were within the methodological error. Total hexosaminidase activity did not change significantly during the entire study period and at different storage temperatures. Conclusions: The two enzymes investigated in the present study may be stored for up to 17 days (β-galactosidase) or 180 days (total hexosaminidase) until analysis without loss of activity.