ALK testing: what it means for you

Waiting on test results can feel like one more hard thing, for you and the people who love you. Here's what the ALK test looks for and how it can help your care team pick the treatment most likely to work for you.

ℹ️ General information to help you and your loved ones talk with your care team, not medical advice. Read our disclaimer.

Matters most in: Lung cancer

The quick guide

What the test looks for: A rearrangement (fusion) of the ALK gene, where part of ALK joins another gene. Found in about 4–5% of non-small cell lung cancers, often in younger people and people who never smoked.

Why it matters

ALK-positive lung cancer usually responds very well to ALK-targeted pills, often for years.

Treatments it can point to

ALK pills such as alectinib, lorlatinib or brigatinib

Only your care team can say which treatment fits you. Drug approvals depend on cancer type, stage and prior treatment.

Tissue vs. blood testing

Tissue (stain, FISH or a gene panel). Some blood tests can also detect it.

Most tests use a piece of tumor tissue from a biopsy or surgery. Some can also use a blood sample (a 'liquid biopsy') that looks for tumor DNA floating in the blood. Blood tests are easier and faster, but they can miss a change that a tissue test would find, so a negative blood test is often followed by a tissue test.

❓ Questions you and your loved ones can ask

Which ALK pill is best for me, and how does it reach the brain?
What happens if the cancer stops responding?
When will my results be back, and will treatment wait for them?
Will my insurance cover this test?

Written by the Cancer Side Effects Guide team from FDA labels and leading cancer centers. Not medical advice. · Last updated: October 15, 2026 · How we write

Not medical advice. This page is general information to help you talk with your care team. It can't replace advice from your doctor or nurse. If you have a fever of 100.4°F (38°C) or higher during treatment, or any symptom that worries you, call your care team now. In an emergency, call 911.