Typically this would be denoted by the term 'intracellular' (vs. extracellular). In your instance, you shouldn't use the term 'hyperglycemic cell' because, as you stated, hyperglycemic refers to blood! If you want to reference a cell with a 'high' sugar concentration, you would say 'elevated intracellular glucose concentration' or 'intracellular glucose level of x'.
Hope that helps!