Sodium chloride for medical use is not sodium chloride for laboratory use?

To be precise, medical sodium chloride should be more pure than the market of non-iodized salt, sodium chloride in chemistry called salt, according to the requirements of chemical reagents: first-class for superior purity (GR), used for scientific research, the second level of analytical purity (AR), used for the majority of the analytical work, the third level of chemical purity (CP), used for general analytical experiments, the fourth level of chemical reagents or medical (LR), used for test auxiliaries, salt is edible. Sodium chloride in the state of crystalline water exists, the purity of sodium chloride is not as high as the purity of medical sodium chloride, some chemical substances plus edible, medical and other words generally refers to its health grade rather than its content, medical sodium chloride is mainly used for the preparation of injection solutions, Taobao, the drugstore should be able to buy.