The abhidhamma is considered the purest distillation of the dhamma. The Buddha is said to have taught it in its whole and related it to Sariputta who organized it into the form that we have it today. We might assume that it has gone through further revisions and alterations, but the essence is certainly from the Buddha and in line with reality and the dhamma.
Relating the suttas to the abhidhamma is difficult because of the difference in their nature; the former make use of conventional truth (sammuti-sacca) while the latter is mostly confined to ultimate truth (paramattha-sacca). They perform different functions. Nonetheless, they are clearly still talking about the same things, and you will find the suttas refer often to the topics of abhidhamma - the senses, the elements, the faculties, etc.