Search, and I think I have posts in another thread on dysgraphia/dyslexia evals. But in brief, you'll be looking for a psych (neuro, school, or clinical), and an OT. The OT documents and diagnoses the fine motor coordination aspect of dysgraphia. The psych documents the cognitive and achievement profile of weaknesses in automaticity, often processing speed or working memory (though not always both), and written expression deficits.

...pronounced like the long vowel and first letter of the alphabet...