well, it doesn't matter which one you pronounce in daily life. Chinese people can understand. However, there is difference between two pronounciation. It depends on the phrases or
sentence. For example, the phrase" 血液", xue is correct. you can't pronounce xie. The sentence "这是血", you should pronounce xie. Most phrase we should pronounce xue, such as " 流血不止,血腥,血肉模糊,血细胞,血迹。"