The manufacturer of anti-MPO reagent (for ANCA testing) has improved the assay thus resolving problems sometimes encountered by the laboratory, which while did not affect patient results, did affect laboratory processes.
This improvement has caused a one-time shift in numerical values downwards. This may be a significant shift in some patient results compared to previous ones using the old reagent. It may also result in less false positives. It should not have any impact on the overall sensitivity of the assay.
The new reagent will be in use from Friday 17th October.
To allow comparison of results using the new reagent versus the old reagent, Pathlab will test positive results obtained by the new reagent in parallel with the old reagent and provide both results in a comment. This will also occur for any newly negative anti-MPO results if the previous result was positive by the old reagent. This parallel testing will only occur once, after which only the new reagent will be used. Results using the new reagent will not be otherwise comparable to the old reagent.