Once routine biochemical and haematological analysis have demonstrated microangiopathic haemolytic anaemia, thrombocytopenia and acute renal failure, investigations are aimed at determining the underlying aetiology. There is no biomarker which will identify complement mediated aHUS at initial presentation and the diagnosis is one of exclusion. We recommend that all patients with a potential new diagnosis of complement mediated primary aHUS are offered treatment with eculizumab. The earlier treatment with eculizumab is initiated the greater the chance of recovery of renal function. If you have a patient with a potential diagnosis of aHUS, please call the Newcastle upon Tyne Hospitals switchboard on 0191 2336161 and ask for the on-call consultant for aHUS. Full details explaining the referral process (and access to our latest forms) are available in our EMERGENCY REFERRAL pathway. Although all investigations on the diagnostic checklist must be undertaken at initial presentation in adults, only the ADAMTS13 activity must be available prior to authorisation of Eculizumab. Until this is available we recommend that plasma therapy is undertaken where appropriate.

Please visit the National Renal Complement Therapeutics Centre website at www.atypicalHUS.co.uk for more information about the diagnosis and management of aHUS, including patients with aHUS who have end-stage renal failure and may benefit from the prophylactic use of eculizumab at time of renal transplantation. If you only require investigations offered by the Northern Molecular Genetics Service to screen for inherited and acquired complement abnormalities that associate with aHUS and you do not need to make an urgent referral for consideration of eculizumab, you can download a form here.