Acute lymphocytic leukemia may be suspected if a blood test shows an abnormal white blood cell count. A doctor can confirm the diagnosis with a biopsy.

Acute lymphocytic leukemia (ALL), also called acute lymphoblastic leukemia, is a type of blood cancer that makes up about 0.3% of all cancers and 2% of blood cancers in the United States.

It’s most common among children, adolescents, and young adults. Half of people who receive a diagnosis of ALL in the United States are under the age of 17.

Doctors use a variety of tests to diagnose ALL. A blood test can reveal a high white blood cell count or a high count of abnormal white blood cells that suggests leukemia.

The diagnosis can be confirmed with a small tissue sample of your bone marrow called a biopsy.

Read on to learn more about how doctors diagnose ALL and which tests they use.

Receiving an ALL diagnosis often starts with a visit to a doctor. Your doctor (or your child’s doctor) will perform a physical exam where they look for potential signs of ALL, such as swollen lymph nodes. They will also consider your symptoms and review your personal and family medical history.

Blood tests

If you have characteristic signs or symptoms of leukemia, your doctor will likely want to perform blood tests. Your blood tests may reveal a high white blood cell count or a high number of abnormal white blood cells.

If your blood test results reveal something concerning, your doctor will likely refer you to a blood specialist called a hematologist.


A hematologist can confirm the diagnosis of ALL and narrow it down from other types of leukemia by taking a biopsy, a small sample of cells from your bone marrow. These cells are examined under a microscope.

A bone marrow biopsy takes about 30 minutes and you can usually go home the same day. The procedure usually involves taking a sample from your hip bone with a long and thin needle.

Other tests

Doctors perform various other tests to help with the diagnosis or see how far the cancer has spread. These include:

  • Immunophenotyping: A laboratory test that can differentiate types of leukemia with a sample of your blood or bone marrow.
  • Polymerase chain reaction (PCR) test: A blood sample can be analyzed with a PCR laboratory test to see if your treatment is working. PCR tests are usually repeated every 3 months for at least 2 years.
  • Lymph node biopsy: During a lymph node biopsy, a sample or an entire enlarged lymph node may be removed to see if the leukemia has spread.
  • Lumbar puncture: A lumbar puncture may be performed if your doctor thinks the cancer may have spread to your central nervous system. It involves inserting a needle into your lower spine to take a small fluid sample for analysis.
  • Computed tomography (CT) scan: A CT scan can help doctors see if the cancer has spread to internal organs.
  • Chest X-ray: A chest X-ray can help doctors see signs of swollen lymph nodes in your chest.

“Acute” means that ALL tends to develop quickly if left untreated, unlike chronic leukemias, which tend to develop slowly.

“Lymphocytic” means that ALL develops in lymphoid cells that become three types of white blood cells:

  • natural killer cells
  • T cells
  • B cells

ALL starts in your bone marrow but tends to spread quickly to your blood. It can also spread to other parts of your body, such as your:

  • lymph nodes
  • central nervous system
  • liver
  • spleen

What’s the difference between ALL and AML?

ALL and acute myeloid leukemia (AML) are both aggressive types of leukemia that develop in the cells that become blood cells.

AML is the most common adult leukemia. It develops in a branch of blood cells called myeloid cells, whereas ALL develops in cells that become lymphoid cells. Myeloid cells become:

  • red blood cells
  • mast cells
  • other types of white blood cells
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ALL symptoms tend to be general and develop gradually over time. They can include:

It’s important to see a doctor if you or your child develop potential signs or symptoms of ALL.

Doctors often use relative 5-year survival rates to measure the outlook of cancers. The relative 5-year survival rate is the likelihood that a person with the cancer will be alive 5 years after their diagnosis compared to somebody without the cancer.

The 5-year relative survival rate of ALL in the United States from 2013 to 2019 was 71.3%.

ALL is the most common childhood cancer. Children are at the highest risk of developing ALL, but they also have the best chance of survival. About 80% of ALL deaths occur in adults.

Here’s a look at how the 5-year relative survival rates vary by age:

Age group5-year relative survival
Under 1592.1%
75 and over13.9%

A blood test is often one of the first tests doctors perform to diagnose ALL. A high white blood cell count or a high count of abnormal cells can be a sign of leukemia.

Doctors can confirm the diagnosis with a biopsy. Other tests, such as lymph node biopsies and CT scans, can help assess how far the cancer has spread.