Although a doctor may suspect a patient has leukaemia based on signs and symptoms, it can only be diagnosed by laboratory tests. The results of a simple blood count will usually indicate leukaemia although, rarely, a blood count may be normal. Most patients with leukaemia will have a bone marrow sample taken to confirm the diagnosis and to help to determine exactly what type of leukaemia a patient has. More specialised tests are often done at the same time.
Usually, a chest x-ray will be taken as well as scans, to look for swollen lymph nodes, or other affected sites. Blood samples will be taken to test for any problems with the liver, kidneys or other organs. In some, but not all, types of leukaemia a sample is taken of the fluid which surrounds the brain and spinal cord – cerebrospinal fluid (CSF). This is because some kinds of leukaemia cells can get into the nervous system, which protects them from most kinds of treatment. Some blood tests and scans will be repeated to check for the response to treatment and any complications. Other tests are usually only done at diagnosis.