One way in which ALL is first suspected comes when we laboratory tests show high levels of leukocytes and presence of immature leukocytes in the blood. However, if the patient also has some of the symptoms mentioned above, complementary tests should be conducted to confirm this suspicion.

Complementary tests include:

• Medical history and physical examination: past history, smoking, exposure to chemicals, previous chemo- or radiotherapy treatment. During the physical exam, doctors will inspect your mouth, skin, lymph nodes, liver, and spleen. They will look for signs of bleeding, spots, or infection.

• Bone marrow aspiration: involves taking a sample of bone marrow (while under local or general anesthesia) or a biopsy; during a biopsy, a small sample of bone is taken following aspiration (usually from the sternum or iliac crest) to assess the precursors of blood cells.

• Cytogenetic testing: of the specimen taken from aspirated bone marrow, analyzing the chromosomes to check whether there are alterations present and whether or not the Ph chromosome is present.

• Fluorescent in situ hybridization (FISH): This test is very similar to cytogenetic testing, though using fluorescent stains. These stains become attached to specific genes or parts of the chromosome, making it possible to determine whether translocation or disappearance of part of a gene (deletion) has taken place.

• Polymerase chain reaction (PRC): This is a highly sensitive test that makes it possible to detect certain genetic and chromosomal changes. It is very useful in finding genetic abnormalities in the absence of confirmed chromosomal alterations. This is useful in cases in which Ph chromosome is negative and for subsequent patient follow-up.

• Lumbar puncture: We analyze cerebrospinal fluid (CSF) by performing a lumbar puncture. It is a common test for this type of leukemia because of the high incidence of CNS infiltration. It allows medication to fight against the disease to be administered directly into the CSF.