Method for detecting or quantifying carbohydrate containing compounds

A method of evaluating a carbohydrate in a sample comprising:

• a) contacting the sample with a specific binding pair which comprises a first binding member and a second binding member;
• wherein the first binding member comprises a low valency carbohydrate binding ligand coupled to a first energy absorbing material,
• said low valency carbohydrate binding ligand having no greater than three carbohydrate binding sites,
• wherein the second binding member is a glycoconjugate which comprises a carbohydrate moiety and a second energy absorbing material;
• wherein the excited state energy level of the first energy absorbing material overlaps with the excited state energy level of the second energy absorbing material;
• and
• wherein the low valency carbohydrate binding ligand and the glycoconjugate reversibly bind to each other such that carbohydrate present in the sample displaces the glycoconjugate and reversibly binds to the low valency carbohydrate binding ligand;
• and
• b) evaluating the extent to which non-radiative fluorescence resonance energy transfer occurs between the first energy absorbing material and the second energy absorbing material,
• thereby evaluating the carbohydrate in the sample.