(Note: this lecture should go near the end of the conference – with audience participation to sum up things learned. Hershey’s kisses are thrown to those chiming in, voicing answers, etc. Folks get involved and it is lots of fun). You are presented with a geriatric pet rat, 24 months old, that is lethargic, with porphyrin staining of the face. We will work through the case on a step-by-step basis, figuring out the differential diagnosis list, diagnostic priorities, evaluating tests and data, formulating a treatment and management plan.