Filter paper blood spot enzyme linked immunoassay for insulin and application in the evaluation of determinants of child insulin resistance.
| Autor: | Martin RM; School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom. richard.martin@bristol.ac.uk, Patel R, Zinovik A, Kramer MS, Oken E, Vilchuck K, Bogdanovich N, Sergeichick N, Gunnarsson R, Grufman L, Foo Y, Gusina N |
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| Jazyk: | angličtina |
| Zdroj: | PloS one [PLoS One] 2012; Vol. 7 (10), pp. e46752. Date of Electronic Publication: 2012 Oct 08. |
| DOI: | 10.1371/journal.pone.0046752 |
| Abstrakt: | Background: In large-scale epidemiology, bloodspot sampling by fingerstick onto filter paper has many advantages, including ease and low costs of collection, processing and transport. We describe the development of an enzyme-linked immunoassay (ELISA) for quantifying insulin from dried blood spots and demonstrate its application in a large trial. Methods: We adapted an existing commercial kit (Mercodia Human Insulin ELISA, 10-1113-01) to quantify insulin from two 3-mm diameter discs (≈6 µL of blood) punched from whole blood standards and from trial samples. Paediatricians collected dried blood spots in a follow-up of 13,879 fasted children aged 11.5 years (interquartile range 11.3-11.8 years) from 31 trial sites across Belarus. We quantified bloodspot insulin levels and examined their distribution by demography and anthropometry. Results: Mean intra-assay (n = 157) coefficients of variation were 15% and 6% for 'low' (6.7 mU/L) and 'high' (23.1 mU/L) values, respectively; the respective inter-assay values (n = 33) were 23% and 11%. The intraclass correlation coefficient between 50 paired whole bloodspot versus serum samples, collected simultaneously, was 0.90 (95% confidence interval 0.85 to 0.95). Bloodspot insulin was stable for at least 31 months at -80°C, for one week at +30°C and following four freeze-thaw cycles. Paediatricians collected a median of 8 blood spots from 13,487 (97%) children. The geometric mean insulin (log standard deviation) concentrations amongst 12,812 children were 3.0 mU/L (1.1) in boys and 4.0 mU/L (1.0) in girls and were positively associated with pubertal stage, measures of central and peripheral adiposity, height and fasting glucose. Conclusions: Our simple and convenient bloodspot assay is suitable for the measurement of insulin in very small volumes of blood collected on filter paper cards and can be applied to large-scale epidemiology studies of the early-life determinants of circulating insulin. |
| Databáze: | MEDLINE |
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