A1C is a lab test that shows the average level of blood sugar (glucose) over the previous 3 months. It shows how well you are controlling your diabetes.
APA guidelines stipulate rules for punctuation, tables, headings, statistics and citations. Citing your sources according to APA style helps you avoid plagiarism and boost your paper's credibility. When you cite or mention a book in a paper, you should italicize the title. Citations of books in your Reference List should begin with the last name of the book's author, then the author's initials.
They would also be italicized in the in-text citation, just like a book. These posts on the APA Style blog will also be helpful: How to Cite Something You Found on a Website in APA Style. Missing Pieces: How to Write an APA Style Reference Even Without All the Information.