save value from intercepted body using cypress

I have the following code:

let test="not-set";
cy.intercept(
    {
        url: '**/consumers/rx?extension=.jpg',
        method:"POST"
    },
    (req) => {
        req.on('response', (res) => {
            // cy.log(res.body.rxId);
            expect(res.body.rxId).not.to.be.null;
            test = res.body.rxId;
            // cy.wrap(res.body.rxId).as('rxId')
        })
    }
)
cy.log(test); // the value will be not-set

How could I save/use the value res.body.id in the follwing test steps