Supra-Regional Assay Service for Renin / Aldosterone
We are transferring our Aldosterone and Renin service to LC-MS/MS. This change was driven by a desire to reduce our analysis time for renin activity (currently in excess of 7 days for 40 % of samples) and accelerated following the announced withdrawal of the commercial aldosterone RIA we have been using.
We have now validated our LC-MS/MS aldosterone assay and will be transferring to it during the week beginning 19th January 2015.
The adult reference ranges for the new assay are:
Aldosterone: 90 – 700 pmol/L
Renin: as previously (0.5 – 3.1 nmol/L/h)
Aldosterone / renin ratio: < 680 Conn’s unlikely; > 850 Conn’s possible; > 1700 Conn’s very likely
As always, paediatric reference ranges will be communicated in comments on reports as necessary.
We believe this will provide a better service for patients compared to the previously used immunoassay as it gives good separation from other steroids. For example, samples run from patients with CAH and probable aldosterone synthase deficiency give much lower results than would be expected from the correlation data confirming suspected possible interference in the RIA method in patients with altered steroidogenesis.
We are committed to providing a plasma renin activity service with high sensitivity at the low end to give clear biochemical diagnosis of primary hyperaldosteronism. We are continuing to develop the LC-MS/MS angiotensin 1 assay for measurement of plasma renin activity and will inform you of all changes in due course. Using LC-MS/MS for both assays will significantly reduce our turn around times compared to our current highly manual methods whilst maintaining a high quality analytical service with clinical interpretation.
Please do not hesitate to contact us if you have any questions.
Mrs Sophie Barnes FRCPath Mr Mike Scanlon
Director, Consultant Clinical Scientist: Deputy Director, Clinical Scientist:
020 331 15183 020 331 15181