Re: How is leukemia detected?
Yes, that's right. 100% diagnosis is by bone marrow biopsy. However, if you have leukemia, they will find blast cell/immature white blood cell in your CBC with differential test, therefore if the test does not find blast cell, almost impossible you have leukemia.
The major symptoms of Leukemia are anemia, tiredness, fever, and bleeding and they will progress rapidly in acute Leukemia (usually less than 6 weeks). If your headaches already there for long time, it will be almost impossible that your headaches is the symptom of Leukemia.
For Chronic Leukemia, usually the doctor will find abnormalities in your CBC with diff, even if you don't have any symptom, but chronic leukemia is very rare among people under age 50.
Headaches could be symptom of many benign abnormalities, such as migrain or hypertension but also could be sign of something more serious. Therefore, ask your doctor to check your headaches.