Autosomal dominant polycystic kidney disease (ADPKD) tends to be diagnosed between age 30-50 because the symptoms do not usually develop during the early stages of the condition.
If you are diagnosed with ADPKD, your GP will probably refer you to a renal consultant or a nephrologist (a doctor who specialises in treating kidney conditions).
Medical history and examination
When making a diagnosis, your GP will ask about your symptoms and your family’s medical history. If your kidneys are enlarged, your GP may be able to feel them in your abdomen (tummy). Therefore your GP may ask to examine your abdomen.
Urine and blood tests
Your GP will measure your blood pressure to see if it is higher than normal. They may also carry out other tests, such as:
- urine tests to check for blood or protein in your urine
- blood tests to check how well your kidneys are filtering waste products from your blood
GFR blood test
An effective way of assessing how well your kidneys are working is to calculate your glomerular filtration rate (GFR). GFR is a measurement of how many millilitres (ml) of waste products your kidneys can filter in a minute. A healthy pair of kidneys should be able to filter more than 90ml.
Calculating your GFR usually involves taking a blood sample and measuring the levels of a waste product called creatinine. If your creatinine levels are higher than normal, it may suggest that your kidneys are not filtering the blood as effectively as they should. A very low GFR rate (15-29ml) would suggest that your kidneys are close to failing.
See the Health A-Z topic about Chronic kidney disease - diagnosis for more information.
Scans
ADPKD can usually be diagnosed in adults using ultrasound scans, which show whether there are any cysts in your kidneys or other organs, such as your liver. Your doctor may therefore arrange for you to have an ultrasound scan.
When making a diagnosis, doctors will consider your symptoms and take into account your age and the number of cysts that are present. This will also help them to assess:
- how much the condition has progressed
- how much your kidneys are damaged
In some cases, your doctor may also arrange a computerised tomography (CT) scan for you, which can show more detail.
If you have a family history of brain aneurysms, some doctors may recommend that you have a magnetic resonance imaging (MRI) scan. A brain aneurysm is a bulge in one of the blood vessels in the brain that is caused by a weakness in the blood vessel wall.
For more information about brain aneurysms, see Polycystic kidney disease - complications and the Health A-Z topic on Aneurysm.
Screening
Screening people who are known to be at risk of developing ADPKD due to a family history of the condition is a controversial issue in the medical community.
Some experts argue that screening achieves little in practical terms. This is because there is no treatment that can prevent a younger person developing ADPKD later in life (although this may change in the future).
Some also argue that by confirming that a person is at risk of developing ADPKD, you are burdening them with the knowledge that they are likely to have kidney failure later in life. This could cause a lot of stress and anxiety.
Other experts argue that although you cannot prevent ADPKD, you can treat the high blood pressure associated with the condition. Beginning treatment as soon as possible could significantly reduce the risk of a person developing a serious cardiovascular disease (CVD), such as heart disease, heart attack or a stroke.
If you are considering being screened for ADPKD, discuss the advantages and disadvantages of screening with your GP, partner and family.
How screening is performed
There are two main methods that can be used to screen for ADPKD. These are:
- using ultrasound to check for any kidney abnormalities
- using genetic testing to determine whether your DNA contains either the PKD1 or PKD2 mutations that cause ADPKD (DNA molecules contain genetic information that determine characteristics such as eye and hair colour)
Neither of these tests is entirely accurate. While ultrasound has an almost perfect record of detecting cysts in people with PKD1, it has a 67% success rate of detecting the condition in people with the PKD2 mutation who are under 30 years old.
Similarly, current genetic testing can only correctly identify when a mutation is present in 65-70% of cases.
