Based on what? Unless we know the whole conversation we don't know that. If the Doctor's office gave any medical information to the nurse without her name being on the release form the parent has on file for her child in the Dr's office then it is a violation. If the nurse provided any medical information on the child to the Dr's office without the parent having an authorization form on file then she too violated the law. But if the nurse simply called and asked Did Dr. Who write a note for Little Suzy on 04/22/08 in regards to her medical problems then the Dr's office could confirm a note was written but not what was written.
School nurses cannot violate HIPPA either. She cannot discuss any students medical problems with anyone other than the parents unless the parents have signed an authorization form. For example she cannot tell the art teacher that Suzy Q has/had xyz medical condition w/o first getting authorization from Suzy Q's parents.
In my case my son was in middle school and was sent home twice for having a cough. After the second time they insisted he be taken to the Dr. He had no other problems just a cough but only at the school. He was prescribed a med to see if it would clear up. A week later the school guidance (yes guidance not nurse) counselor left me a phone msg saying that he thought DS was diabetic or was having panic attacks...but he really thought it was diabetes. After hearing that I was beyond mad.

Since when can a guidance counselor diagnosis a child with diabetes because they have a cough!!??!! So the next morning I kept DS home, called the school and the school secretary asked me if I was taking DS to the Dr to get something done about his diabetes. I ignored her question and asked for the school receptionist because that's who you had to talk to about absences....she asked the same thing. Unfortunately I am related to her(but can't stand her) but still it's none of her business!! I informed her he was not diabetic and that her quack of a counselor better shut his trap or I was going to the school board. She insisted he had experience in knowing what was wrong with the students because he's seen it before. Ohh and the school nurse...they never told her about any of this! I took DS to the Dr yet again and she said possibly he could have a problem with something in the school causing allergies or slight asthma. When I mentioned the diabetes she was mad. She called her nurse in and had her write a note to the school saying DS was not a diabetic, he had a cough that was not contagious, did not need to return to her office and he was cleared to attend school. She told me if they didn't stop sending DS home to call her and she'd personally call the school and put a stop to the problem. Funny how the guidance counselor was not available the next morning to receive the Dr's note....nor did he ever return my calls.
Fast forward a few months.......Older DS had to write out a 4 year plan for high school classes at the HS. So there's this guy walking around helping everyone......everyone but us. I was a lil miffed and asked DS why the guy never came over to help him. Well, seems that the "guy" was the guidance counselor from the middle school and he knew that the boys were brothers so he avoided us totally. When we turned in the form the lady asked if Mr. Jerk had checked it over and I told the truth...Nope, he's avoided us since we arrived and was of no help.