A puncturing device for generating a puncture wound to sample a body fluid is provided and comprises a press-on part or contact element to be pressed against a body part to generate a puncture, a test sensor for measuring a test parameter value, and an analytical unit for determining whether the value of the measured test parameter satisfies a predefined minimum requirement for successful sampling. In one embodiment, the value of the test parameter is monitored during a waiting period by the test sensor once the value satisfies the predefined minimum requirement. After the waiting period has elapsed, so long as the values of the test parameter monitored during the waiting period are in a range of values that predicts sampling to be successful, the analytical unit initiates a puncture.