Patent ID: 7083982

Claim:
A method of detecting and enumerating reticulocytes in a test sample comprising the steps of: a. providing a test sample; b. adding to said test sample a dye having the formula: wherein: R 1 , R 2 , R 3 , R 4 independently represent a member selected from the group consisting of hydrogen, halogen, aryl having more than one ring; R 5 represents an alkyl group having 1 to 6 carbon atoms or an aryl group having no more than one ring; R 6 , R 7 , R 8 , R 9 independently represent a member selected from the group consisting of hydrogen, halogen, alkyl having 1 to 6 carbon atoms, aryl having no more than one ring, provided that at least one of R 6 , R 7 , R 8 , R 9 represents halogen; R 10 represents an alkyl group having 1 to 6 carbon atoms or an aryl group having no more than one ring; R 11 , R 12 independently represent a member selected from the group consisting of hydrogen, halogen, alkyl having 1 to 6 carbon atoms, aryl having no more than one ring; R 13 represents hydrogen or an alkyl group having 1 to 6 carbon atoms; Y represents S, O, C, or Se; n represents 1; and X − represents a counter ion, and c. measuring the fluorescence of said test sample to detect and enumerate reticulocytes in said test sample.