Yes it is a red crab spider
Its a black widows cousin african bunnie spider. It will make you sick with urinary problem's
What kind of spider is kind of small with a white butt area and a red stripe going up the center?? Is it poisonous?
It sounds like it could be a Goldenrod crab spider. Its very small in size, white body with red stripes down the side. Hope this sounds like the spider you have seen.