Doctors classify acute lymphoblastic leukemia (ALL) into subtypes by using various tests. It's important to get an accurate diagnosis since your subtype plays a large part in deciding the type of treatment you'll receive.

Common testing used to classify ALL subtypes include immunophenotyping and cytogenetic analysis. Some of these tests may be repeated during and after therapy to measure the effects of treatment. Your doctor must identify the immunophenotype and any abnormalities in your chromosomes to determine:

• The intensity of the drug combination needed for your treatment
• The length of time you'll need to be in treatment

The two main ALL subtypes, B-cell ALL and T-cell ALL, are determined by immunophenotyping. Most people with ALL have the B-cell type. Most cases of B-cell ALL begin in a cell called a precursor B-cell.

Doctors use the following terms to further describe ALL subtypes:

• Acute B-lymphoblastic leukemia
• Acute precursor B-cell leukemia
• Pre B-cell lymphoblastic leukemia
• Philadelphia-positive ALL (Ph+ ALL)
• Acute T-lymphoblastic leukemia
• Natural killer (NK) cell leukemia