Acetoacetate is a primary ketone body. Beta hydroxy butyrate and acetone are secondary ketone bodies. Acetoacetate can be formed from acetyl CoA, it can also be formed by the degradation of carbon skeleton of ketogenic amino acids like leucine, lysine, phenylalanine and tyrosine. Acetone is formed by the degradation of carbon skeleton of acetoacetate. Beta hydroxy butyrate is formed by the reduction of acetoacetate Ref: Textbook of Biochemistry By D M Vasudevan, 3rd Edition, Page 131