Evaluation of a commercially available radioimmunoassay and species-specific ELISAs for measurement of high concentrations of insulin in equine serum
| Autor: | Kate Borer-Weir, Jonathan Elliott, Simon R. Bailey, Patricia A. Harris, Nicola J. Menzies-Gow |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Male
medicine.medical_specialty Swine medicine.medical_treatment Radioimmunoassay Enzyme-Linked Immunosorbent Assay Sensitivity and Specificity chemistry.chemical_compound Species Specificity Limit of Detection Internal medicine medicine Animals Humans Insulin Horses Dexamethasone General Veterinary Insulin blood business.industry C-peptide High serum Reproducibility of Results General Medicine Repeatability Laminitis Endocrinology chemistry Female business medicine.drug |
| Zdroj: | American journal of veterinary research. 73(10) |
| ISSN: | 1943-5681 |
| Popis: | Objective—To evaluate a human radioimmunoassay (RIA) and equine and high-range porcine (hrp) species-specific ELISAs for the measurement of high serum insulin concentrations in ponies. Samples—Serum samples from 12 healthy nonobese ponies (7 clinically normal and 5 laminitis prone; 13 to 26 years of age; 11 mares and 1 gelding) before and after glucose, insulin, and dexamethasone administration. Procedures—Intra-and interassay repeatability, freeze-thaw stability, dilutional parallelism, and assay agreement were assessed. Results—Assay detection limits were as follows: RIA, < 389 μU/mL; equine ELISA, < 175 μU/mL; and hrp ELISA, 293 to 8,775 μU/mL. Mean ± SD intra- and interassay repeatability were respectively as follows: RIA, 6.5 ± 5.1 % and 74 ± 3.4%; equine ELISA, 10.6 ± 11.0% and 9.0 ± 4.6%; and hrp ELISA, 19.9 ± 172% and 173 ± 16.6%. Freezing and thawing affected measured concentrations. Dilutional parallelism in the RIA was only evident when insulin-depleted equine serum was used as a diluent (percentage recovery, 95.7 ± 274%); in the ELISAs, dilutional parallelism was observed when a zero calibrator was used. Agreement between RIA and equine ELISA results was good for samples containing concentrations < 175 μU of insulin/mL (bias, −18.5 ± 25.5 μU/mL; higher in RIA). At higher concentrations, assay agreement was poor between RIA and equine ELISA results (bias, −185.3 ± 98.7 μU/mL) and between RIA and hrp ELISA results (bias, 25.3 ± 183.0 μU/mL). Conclusions and Clinical Relevance—Agreement among results of the 3 assays was variable, and dilutional parallelism was only evident with the RIA when insulin-depleted equine serum was tested. Caution is recommended when evaluating high insulin concentrations measured with the RIA or ELISAs. |
| Databáze: | OpenAIRE |
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