Cross-reactivity of 12 recombinant insulin preparations in the Beckman Unicel DxI 800 insulin assay.
BACKGROUND
Insulin analogues used in the treatment of insulin-dependent diabetes may result in hypoglycaemia; however, these preparations show variable cross-reactivity in many insulin assays. In order to investigate a suspected insulin overdose, it is therefore essential to characterize the cross-reactivity of these preparations in insulin assays.


METHODS
The cross-reactivity of 12 commercial insulin preparations was assessed on the Beckman DxI analyser, by comparison with the insulin calibration curve corresponding to the midpoint of the dose-response curve. This was achieved by manually plotting the relative light units generated by the analyser for each preparation.


RESULTS
All 12 insulin preparations examined showed significant cross-reactivity with the Beckman DxI insulin assay, with 11 of the insulin preparations demonstrating cross-reactivity of 83% or greater. The lowest cross-reactivity was observed with detemir with a value of 47.6%.


CONCLUSIONS
When investigating hypoglycaemia it is important to be aware of the cross-reactivity of the recombinant insulin analogues in insulin assays. This study has established the cross-reactivity of 12 preparations in the Beckman DxI insulin assay.
Glenn
Christine
C
Endocrine Laboratory, Laboratory Medicine, Mail point 087, Level D, South Academic Block, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, UK.
Armston
Annie
A
D001681:Biological Assay / Q000379:methods; D003429:Cross Reactions; D006801:Humans; D007004:Hypoglycemic Agents / Q000032:analysis*; D007118:Immunoassay; D007328:Insulin / Q000031:analogs & derivatives* / Q000032:analysis*
D007004:Hypoglycemic Agents; D007328:Insulin