I vividly remember Tigger's first appointment with current psychiatrist (Tig was 7 or 8) and while I got him into the waiting room he refused to go into the doctor's office. The psychiatrist (huge man) walked out, looked at me and said he'd handle it. He reached under the chair where Tigger was hiding, flipped him over his shoulder and strode into his office. I scurried in after him and pulled my chair to block the door.
Tigger was unable (not really unwilling just couldn't focus enough) to be tested for a long time.
A parent report is very key. It will allow the npdoc to get a place to start.