I took the CCS exam a couple of years ago and it was considerably more challenging than the CPC exam in my opinion. It requires a very strong knowledge of diagnosis coding guidelines, rules, and Coding Clinics, and you have to do it all very quickly to beat the time limit.
This is a test that novice or newly credentialed coders are likely not well equipped to take without a program or course as additional help. But a seasoned outpatient coder can do it on their own, as long as you are prepared.
A couple of resource tips for CCS examinees:
1. Get yourself a Faye Brown to help you learn the ins and outs and basic mechanics of diagnosis coding. What you may have learned about ICD-9 in order to pass the CPC will definitely not be enough
2. You should also study pathophysiology, anatomy and physiology, and pharmacology to give you a better background of the drugs, anatomy, and the disease processes themselves
3. Memorize (or at least strongly familiarize yourself with) the "Official ICD-9-CM Guidelines for Coding and Reporting", usually the first 35 pages in the front of the ICD-9-CM. Since the guidelines are in your ICD-9, you can actually use them during the exam and this is not cheating, but in order not to waste precious time during the exam you have to know what section to quickly thumb to to find the answer you need
4. Get the official AHIMA CCS study guide. Although, a friend who bought the book this year said it was rife with errors, but the year that I took it I didn't find many errors. I also used a Carol Buck review guide, but the Carol Buck was not nearly as helpful as the offical AHIMA guide. The AHIMA guide uses actual questions from the exam, and I actually found that there were some questions ended up on the test that I actually remembered word for word from the review guide. The included CD also has a timed practice multiple choice exam that helps a lot
About the exam itself, the multiple choice questions are extremely difficult, the kind of questions where almost all of the choices look reasonable, so it's very difficult to eliminate potential wrong answers. There are 13 cases to abstract, and they were also very challenging to complete in the time alotted.
A tip for the case abstracting: the year I took it (I say that because I'm not sure if it's changed) the principal diagnosis was worth something crazy like 13 points, and each additional diagnosis was only worth 1 point. So it was easy to get wrapped up in a single case trying to code as many secondaries as possible, but the real strategy is to get that principal diagnosis right and make sure you score that 13 point chunk and not get wrapped up in adding too many secondaries that are only worth 1 point.
And no matter which section of the test you're on, you have to be aware of the clock at all times, clock management is vital to passing that exam.
Best of luck!
Rich Carrillo, CCS, CPC