How is aHUS diagnosed?
There is no definitive test for aHUS – a diagnosis is usually made by performing certain blood tests and ruling out other similar conditions.
Common tests will include:
Full blood count – this is to look at the level of platelets and haemoglobin in your blood
Urea & Electrolytes – this assesses your kidney function
Lactate Dehydrogenase (LDH) – this can be raised during an episode of aHUS due to the breakdown of red blood cells
Haptoglobins – these can be low during an episode of aHUS as haptoglobins attach to the haemoglobin released when red blood cells break down
Complement studies – to measure the levels of complement proteins (C3, C4) and protector proteins (Factor H, Factor I & CD46) in your blood
Genetic testing – to see if you carry any of the known genetic faults associated with aHUS
Blood film – this examines your blood cells under a microscope to look for broken or damaged cells
ADAMTS13 – an enzyme that is reduced in the haematological disease TTP, this test is used to exclude this disease
Stool and blood sample – to exclude ‘typical’ HUS, also known as STEC HUS, E-Coli HUS or diarrhoea positive HUS
Urinalysis – looks for evidence of blood and protein in your urine that can indicate kidney damage
Ultrasound – a non-invasive scan that provides a general outline of the size and shape of your kidneys
Biopsy – a small piece of kidney tissue is removed and looked at under a microscope. This provides a more accurate picture of what may be causing the damage to the kidney
ECG and/or echocardiogram – to look for evidence of long-term high blood pressure that might cause kidney damage
In addition there are a number of other tests that may be carried out to exclude other diseases that present in a similar way. Your local team can provide an explanation of these if required.