ICD-9 vs. ICD-10
In one example a CMS executive gave me, the new codes will impact patients and insurers in quite basic ways. Here's the scenario she gave me. Under ICD-9: In April, Johnny falls off a neighbor's tree, breaks his left arm, and goes to the hospital. Doctors fix him up and insurance pays. In May, Johnny falls off the same neighbor's tree, breaks his right artm, goes to the hospital, doctors fix him up -- but insurance balks, saying "We already paid for this." That's because ICD-9 doesn't specify right or left limb. Under ICD-10, the doctor has to state s/he is working on the left or right arm. The insurance company sees it's a different arm and paperwork goes through smoothly.
Of course, klutzy little Johnny who likes trespassing could ostensibly continue to break the same arm. But at least if he alternates arms it'll be easier for his parents to get the bills paid -- until they finally ground him or the neighbor gets a mean dog and/or a taller fence.