A blood testing apparatus includes a device for withdrawing blood, a membrane-type testing element, an evaluating device, and a display device forming a complete system which can be manipulated as a single piece of apparatus. Multiple testing elements can be inserted into the apparatus and brought successively to a work position for carrying out several measurements. The blood withdrawing device includes multiple pricking elements. One pricking element is pushed through one testing element and pricks the surface of the skin of a user. The pricking position is disposed so that blood withdrawn from the surface of the skin can impinge upon the testing element.