What’s the difference between SNOMED and the ICD siblings, 9 and 10? Many blurbs call SNOMED a Clinical Terminology while the ICD pair are called Classifications.

Terminologies are said to be granular things, meant to handle every medical nuance. They’re said to shine when precision is called for but to be too chatty for summary. That’s why billing calls for Classifications, which capture only the essential. It’s such a neat split – express any and all clinical findings in expansive terminology, but state bills and summarize care in succinct classification but is it too neat?

Consider SNOMED’s definition of Nuclear sclerotic cataract …

a Disease (64572001) with
    :finding_site :56707006 # Nucleus of lens
    :associated_morphology :128305008 # Opacity

You see a terminology doesn’t just give you a concept – it builds it from more primitive definitions. What’s more, though some building is done for you, the assumption is that there will always be more to say and that you need to be able to roll your own. So though basic SNOMED doesn’t come with Senile Nuclear sclerotic cataract pre-canned, you can make it yourself. Just enhance Nuclear scleroitic cataract with …

    :occurrence :271872005 # old age

and hey presto Senile Nuclear sclerotic cataract!

And a classification like good ol’ ICD 9, what does it have to say? Senile nuclear sclerosis (366.16), that’s what. Take that SNOMED! Now being a classification, I9 doesn’t build up slowly to this concept, no layering attribute on attribute for it. A few jumps down its rigid hierarchy gives you …

    Cataract (366)
        Senile Cataract (366.1)
            Senile nuclear sclerosis (366.16)

and though this path provides little for analytical tools, the end result has the same nuance as our newly fired SNOMED.

What’s more ICD 10 is even more expansive. It adds which eye is affected to make Age-related nuclear cataract, right eye. Not only do we get a condition, not only do we get the stage in life of the patient but we also get the eye. Your answer SNOMED?

    :finding-site 
        [ a :56707006 # Nucleus of lens
          :laterality :24028007 # right
        ]

or the disease in question is found in the nucleus of the right lens..

This ability to keep defining means SNOMED won’t loose the contest for breath, no matter how many expressions the ICDs gobble up, but who now gets to lift the cup for essence? Classification-bloat belies our neat split – Classification for essentials, Terminology for expressiveness.

Today, it may be better to say that a Terminology provides a man with some fish and a rod to catch more while a Classification aims to give him all the fish he can eat, ever. Here are two approaches to comprehensive expression and ironically, it’s the terminology that, at its core, is more succinct.

But where, oh where does this leave billing? Using the latest Classification of course. That’s what ICD 10 CM is for and it’s just the size to fit the bill, isn’t it?