How do you evaluate for active tobacco use in patients with advanced CKD who are being evaluated as potential kidney transplant recipients at a center that requires smoking cessation prior to listing?

This is very center-specific. I have been at centers that confirm the recipient has quit smoking with cotinine testing, which can be done on blood, saliva, or urine. Cotinine has a half-life of 15-20 hours and can be detected up to a week post-exposure. One problem is that if the recipient is expose...