How is it diagnosed?

To diagnose aplastic anaemia there must be at least two of the following:

haemoglobin concentration (Hb) <100 g/L

platelet count <50 x 109/L

neutrophil count <1.5 x109/L.

However, aplastic anaemia cannot be diagnosed by a blood test alone. A blood test will highlight there is a low blood count, but further tests are needed to rule out other conditions which also cause low blood counts. These tests include:

A full blood count including checking the number of young blood cells called reticulocytes

Checking your iron, vitamin B12 and folate levels to ensure your anaemia is not caused by nutritional problems

Screening for autoantibodies

Checking your chromosomes to rule out certain inherited types of aplastic anaemia such as Fanconi anaemia

Checking your liver function and for viruses such as hepatitis A, B and C, HIV, Epstein-Barr virus (EBV) and parvovirus

Screening for a rare blood condition called paroxysmal nocturnal haemoglobinuria (PNH).  

In addition to these tests, you will also need to have a bone marrow aspirate and bone marrow trephine. A bone marrow aspirate is obtained by pushing a hollow needle into the bone marrow cavity at the back of the pelvis and sucking out a small quantity of marrow tissue that can then be examined in a laboratory. The sample is used to rule out some inherited forms of aplastic anaemia and various other acquired disorders. When the aspirate is taken you may feel a pulling sensation but this passes off almost immediately.

A bone marrow trephine involves taking a small piece of bone with the marrow tissue inside. It is usually obtained at the same time as the aspirate. The trephine indicates whether the bone marrow contains normal amounts of stem cells. This is called the cellularity of the bone marrow. As we get older the proportion of the marrow which actively produces blood cells decreases so cellularity will vary. When the trephine biopsy is taken you may feel a pushing sensation or a feeling of pressure building up.