Tests used during diagnosis
Diagnosing Gaucher disease can be difficult for several reasons:
- As the disease is so rare, many doctors have not seen or heard of it before and may not consider it as a possible diagnosis.
- Many general signs and symptoms of Gaucher disease (such as feeling tired and pain in joints) can easily be confused with those of more common conditions. For example, doctors may suggest that joint pain is due to arthritis, or bone pain in the upper legs is due to ‘growing pains’ in children. Additionally, symptoms like enlarged spleen and bleeding are often confused with cancers of blood cells and bone marrow (e.g. leukemia).
- Gaucher disease can affect many parts of the body, with different people often affected in different ways and making it hard to tell if the problem is Gaucher disease.
It can sometimes take many months or even years for people with Gaucher disease to get a diagnosis. This can be a long process, involving several different doctors and a wide variety of tests. The usual process is for doctors to rule out more common conditions and blood cancers before thinking about rare disorders such as Gaucher disease.
Some of the key tests used in the diagnosis of Gaucher disease include:
- Blood tests
The most important test to confirm that people have Gaucher disease is a simple blood test (sometimes this is called an enzyme activity assay) to see if a person has low levels of acid-β glucosidase activity. In people with Gaucher disease, the activity levels of this enzyme can sometimes be 70-90% lower than in patients without Gaucher disease. These are sometimes done used ‘Dried blood spots’ as small amounts of blood are dried onto filter paper and then tested to see if the level of activity of the enzyme is normal. Testing can also be done using a blood sample collected in a tube or by testing skin cells called fibroblasts to measure acid-β glucosidase activity.
Testing samples of blood, skin and other body material (samples of skin and other body tissues are called biopsies) also helps to find other potential signs of Gaucher disease such as low red blood cell levels, low platelet counts, low levels of vitamin B12 and high cholesterol levels, although these do not definitely confirm Gaucher disease.
- Genetic tests
When Gaucher disease is first diagnosed in someone they may also have some more tests to find out what defects in their GBA1 gene are causing the disease. This is called ‘genotyping’ and can give useful information about how the disease may continue in the future. A person with Gaucher disease and their family may be offered counselling at this stage so they can learn about how this will impact their lives.
- Microscope test
An old fashioned way of testing for Gaucher disease was to look at a small sample of bone marrow under a microscope to check for Gaucher cells. However it can sometimes be difficult to tell if they are Gaucher cells or cells seen in other blood diseases and so this test is not used to definitely establish the diagnosis of Gaucher disease.
There are also many other tests to see how Gaucher disease is affecting different parts of the body. These include:
- X-rays, magnetic resonance imaging (MRI) or computerized tomography (CT) scans to check for bone disease and to measure the liver and spleen volume (Ultrasounds can also be used for measuring liver and spleen sizes);
- questionnaires to find out how a patient is feeling, and how everyday life works for them.