title: Parathyrin assay. An analytical evaluation of two commercial Immuno Radiometric Assay kits.
abstract: We have performed a comparative evaluation of two Immuno Radiometric Assay (IRMA) kits for parathyrin against an existing Radioimmuno Assay (RIA) technique for the measurement of intact parathyrin. The analytical evaluation which was performed in line with the ECCLS recommended kit evaluation protocol showed a marginal improvement in precision with the new assays. There was a substantial improvement in the theoretical limit of detection utilising the IRMA kits although it may prove difficult to realize this improvement in practice with individual samples because of differing protein matrices. The evaluation also demonstrated the degree of parallelism and range of linearity of both kits as well as inaccuracies when compared with the International Reference Preparation for parathyrin (IRP 79/500) as the accepted standard. The demonstration of lack of agreement between measured and kit assigned results for standards when cross-over studies between kits were performed may highlight a possible contributing factor to inaccuracy. Alternatively there may be a difference of antisera avidity within the kits for intact parathyrin. Whilst minor differences in sample stability were demonstrated between the kits, the sample stability was much improved compared to that for intact parathyrin measurement by RIA. The correlation studies showed a degree of correlation consistent with other comparisons similarly performed.
authors.affiliation: Department of Biochemistry, Dewsbury District Hospital, United Kingdom.
authors.forename: D R
authors.initials: DR
authors.lastname: Pledger
authors.forename: C
authors.initials: C
authors.lastname: Carr
authors.forename: T I
authors.initials: TI
authors.lastname: Sims
authors.forename: K R
authors.initials: KR
authors.lastname: Johnson
mesh_terms: D004305:Dose-Response Relationship, Drug; D005069:Evaluation Studies as Topic; D006801:Humans; D015592:Immunoradiometric Assay / Q000379:methods*; D010281:Parathyroid Hormone / Q000097:blood*; D011933:Reagent Kits, Diagnostic / Q000592:standards
chemical_list: D010281:Parathyroid Hormone; D011933:Reagent Kits, Diagnostic