Hayem Solution

Hayem Solution (NaCl), a liquid used for diluting red blood cells in counting chambers for their enumeration in a hemocytometer. It has the following composition in Hayem's formula: mercuric chloride-0.5, sodium sulfate-5.0, sodium chloride-1.0, distilled water-200.0. It is considered the best preservative solution for red blood cells, which can remain in the counting chamber for hours without any changes. Before use, the solution must be filtered. Pappenheim proposed the following modification of Hayem's solution: mercuric chloride-1.0, sodium chloride-2.0, sodium sulfate-7.5, distilled water-200.0. To 250 cubic centimeters of this solution he adds 0.1 Methylviolet, Toluidine blue or Cresyl blue for better recognition of leukocytes by their stained nuclei and to prevent their confusion with red blood cells during counting.