Evaluation of a new Sebia isoelectrofocusing kit for alpha 1-antitrypsin phenotyping with the Hydrasys System.

BACKGROUND

Laboratory evaluation of alpha 1-antitrypsin (A1AT) deficiency is generally performed by determination of A1AT concentrations and identification of specific allelic variants by phenotyping. For this purpose, we evaluated a new Hydragel 18 A1AT Isofocusing kit on the semi-automatic Hydrasys System (Sebia) for the determination of A1AT phenotypes by isoelectrofocusing on ready-to-use agarose gels with specific immunological detection.

METHODS

Serum samples from 66 patients were analysed with this new kit in comparison with the conventional and manually performed isoelectrofocusing method on polyacrylamide gels with Coomassie Blue staining.

RESULTS

A1AT phenotypes showed comparable iso-electrofocusing patterns in both systems. The good within-gel reproducibility of this kit was demonstrated using two normal serum samples (M1 and M1M2 phenotypes) and six pathological serum samples with different phenotypes (MS, SS, SZ, MZ, ZZ). A sensitivity study was undertaken by performing serial dilutions on a serum with a ZZ phenotype containing 0.27 g/L A1AT. The detection limit was 0.050 g/L.

CONCLUSIONS

This new method is highly specific, rapid and simple to perform. It improves identification of not only the most common but also various rare A1AT phenotypes. It appears to be suitable for routine analysis and screening applications in a clinical laboratory setting.