HI guys,
I don't know if this is the right place to ask but.. i've been really worried. I've noticed bruises on my legs and I don't think that i've been bumping my legs into anything. I heard that bruising is related to lukemia. I always worry about little things but what are the symptoms of lukemia? Thanks

Leukemia can only be accurately diagnosed through rigourous blood and bone marrow testing; typing of the specific leukemia often requires DNA analysis.

Most leukemia symptoms that are visible to the naked eye, or that are noticeable to a person [layperson or doctor] can also be symptoms of other diseases. This is why the lab tests are done - to make sure of the diagnosis.

Can it be recognised through a simple blood test?

A CBC [complete blood count] with differential blood test would show most blood abnormalities, including possible leukemia.

Suggest you visit labtestsonline.org or MedLinePlus for more information on blood tests.