Participant ID - Categorical?

Hi all,
I'm performing a Binary Logistic Regression on data from human subjects. I want to ensure that the effect of independent variables is independent of any individual variation in participants (there are many hundreds of data points per person).

Each person has a unique number identifying them, and this is classed as a Nominal variable in SPSS. When I perform the regression I am classing this variable as categorical. The way I see it, and individual is in one of the categories of participant IDs. However, is this correct?