Hi all
We were able to participate in a sample exchange with a lab running the Abbott assay (we use the Roche assay) which has allowed us to look at the concordance between the Roche and Abbott antibody assays.
There were only 21 samples in total.
In summary:
- All the samples negative by the Roche assay were negative by the Abbott assay
- All the strongly positive samples by the Roche assay (defined as > 60 COI in this sample) were also positive by the Abbott assay.
- Disagreement appears to be over what I would describe as weak positives. These were samples with results on the Roche assay in the range 1 - 5 COI. They were all, apart from one, negative by the Abbott assay.
I believe that the Abbott assay is specific for IgG nucleocapsid antibodies whilst the Roche assay should detect all nucleocapsid antibody isotypes. This seems like one obvious reason for the discrepancy.
I thought I'd share to add to the data in this area.
I'll be interested to see what the EQA schemes show.
Regards,
Gavin
