Sir,The recent report on cerebrovascular ultrasonography is very interesting.[1] Bathala et al., described an intensive detail on medical procedure of cerebrovascular ultrasonography.[1] As noted, the pitfalls can be seen.[1] In fact, the additional concern on the quality control of using cerebrovascular ultrasonography should be raised. In diagnostic medicine, the quality control covering all phases, pre-, intra- and post-diagnostic phase is needed. The described procedure by Bathala et al., is important for intra-diagnostic phase. Additional, pre- and post-diagnostic phase quality control must be applied. The high rate of pre-analytical error in the well-certified diagnostic center is detectable.[2] Hence, it is no doubt that the pre-analytical error can be seen in case of cerebrovascular ultrasonography. The examples of pre-analytical error can be due to patient misidentification, poor patient preparation, poor ultrasonographer tool, etc. The post-analytical error can be record error, misinterpretation, etc. The total quality management by all step quality control for cerebrovascular ultrasonography can help increase clinical accuracy and usefulness of this diagnostic test.