Ask Dr. Pierson and Dyslexia Reflections

My daughter can spell but has been assessed as having a reading rate (not comprehension) that is two years behind her age average. Her reading was assessed by a literacy teacher at her secondary school. She was assessed as she is consistently way slower at her work than her peers (despite apparent concentration), though given time she does well. Given that she can spell does this rule out dyslexia? Is there some other learning difficulty that I should have her assessed for?