Diagnosis of aHUS

Diagnosis of aHUS

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.

The most urgent test is an ADAMTS13 assay which is a prerequisite for Eculizumab initiation in adults. In children due to the rarity of TTP and the difficulty of plasma exchange Kidney Disease: Improving Global Outcomes (KDIGO) recommended that Eculizumab can be commenced prior to the ADAMTS13 result with the caveat that clinical deterioration on eculizumab should necessitate immediate plasma therapy.

Other differential diagnosis of complement mediated aHUS must be sought (see below) however they are not required prior to initiation of Eculizumab. Click on the following for more information about each of the important differential diagnoses:

STEC-HUS | TTP | Secondary TMAs

The following diagnostic criteria for aHUS have been agreed by the aHUS Rare Disease Group:


Thrombotic thrombocytopenic purpura

Shiga toxin associated HUS

Drug induced TMA

Infection (HIV, Streptococcus pneumonia)

Transplantation (bone marrow, liver, lung, cardiac)

Cobalamin deficiency

Systemic lupus erythematosis

Antiphospholipid antibody syndrome


Glucose 6 Phosphate deficiency

Evidence of systemic infection 


Renal biopsy showing a thrombotic microangiopathy


Triad of microangiopathic haemolytic anaemia, thrombocytopenia and renal failure 



If you have a  patient with a potential diagnosis of aHUS and you would like your patient to be considered for treatment with eculizumab, please follow our guidance and referral pathway as set out in EMERGENCY REFERRALS