Patent ID: 7670793

Claim:
A method of enumerating the number of CD4+ lymphocytes in a cell sample, comprising: a) determining the absolute number of CD45+ white blood cells in the cell sample; b) determining the proportion of CD45+ white blood cells in the cell sample which are CD4+ lymphocytes via flow cytometry by: (i) defining a primary population of CD45+ white blood cells; (ii) defining a secondary population, within said primary population, of all CD4+ lymphocytes having CD4 Bright /low side scatter expression; and (iii) calculating the proportion of CD45+ white blood cells which are CD4+ lymphocytes; and c) multiplying the absolute number of CD45+ white blood cells obtained in step (a) by the proportion of CD45+ white blood cells which are CD4+ lymphocytes obtained in step (b), thereby determining the absolute number of CD4+ lymphocytes in the cell sample; wherein step a) and step b) can be performed in either order.