Similar to ICD, there are other terminologies to describe various domains of the medical world. In this lesson, we will discuss SNOMED, CPT, LOINC, and drug terminologies such as RxNorm. Each of these covers a specific domain such as procedures of labs, and each has a specific structure just as we would expect from an ontology used to describe complex phenomenon. Once the lesson is over, you will be able to match different terminologies such as SNOMED, CPT, LOINC drug terminologies such as RxNorm with different descriptive domains. Moreover, you will be able to contrast the different ways of organizing the information into hierarchies or other categories that facilitates analytical computation. Let us start now with SNOMED-CT. After looking at the ICD representations, we will now look at a terminology that was developed to represent clinical care in contrast to billing. SNOMED-CT is the systemized nomenclature of medical clinical terms. This is the most comprehensive clinical terminology, and it supports with some informaticists call Poly-hierarchical knowledge representation. This means that a concept can have more than one parent. In contrast, consider the simpler situation of ICD-9 and ICD-10 that are hierarchical. You can get more and more granular as you move down the code from left to right. But there's a hierarchical approach to this. One code is numerically represented. The code below this is a specification of a more specific representation of that higher level code. SNOMED-CT includes over a 100,000 clinical findings. These pre-coordinated concepts for common terms allow analysts and clinical experts much more flexibility for post coordinated building of terms. This allows analysts to be very flexible when expressing clinical reality. For example, analysts can essentially use SNOMED like a language to put together sentences or phrases to identify a term or a patient's condition. However, if left unchecked, this flexibility can lead to nonsensical phrases. For example, a broken arm makes sense, but a broken brain likely does not. But that's the price for having such flexibility in coding, and it requires a deeply knowledgeable staff to really represent clinical terms encoded systems. What's the difference between SNOMED-CT and ICD? ICD-9 and SNOMED are far apart in terms of their alignment. ICD-10 is more aligned with SNOMED than ICD-9. There more codes in ICD-10 to align with the SNOMED terms. ICD-11 on the other hand, is expected to be exactly aligned at least for the first few levels of SNOMED-CT according to Dr. Chris Chute of the Mayo Clinic, who was the chair of the steering committee for ICD-11. A crossmap between SNOMED-CT and ICD exists for ICD-9 or ICD-10. The crossmap for SNOMED-CT and ICD-11 will just be the same code for the first few levels of the SNOMED hierarchy, but these are directional crossmaps. Thus depending on the need, a crossmap between SNOMED and ICD can be made from SNOMED to ICD, if you're looking to bill for someone that's characterized incident in SNOMED term and in which case these aren't directional. A SNOMEDterm can be converted to ICD-9 or 10 if you have a record that needs to be assigned the proper code. This is a SNOMED ICD directional mapping. Some of the catch-all codes that are available in ICD, are not available in SNOMED. For example, NEC or NOS which represent, Not Elsewhere Classified or Not Otherwise Specified are not used in SNOMED-CT. But these ICD terms are generally useless terms, and it's much more beneficial to use SNOMED-CT than any level of the hierarchy. The more granular and specific SNOMED concepts are much more useful in building out post coordinated terms. Now, let's move on to the coding of procedures. The Current Procedural Terminology or CPT, is a registered trademark of the American Medical Association. This is a very widely accepted nomenclature for medical procedure reporting. It is maintained by the CPT editorial panel, and it's quite a bit of overlap with ICD in terms of procedure terminology. This is especially true for the ICD-10 code with its 87,000 terms for procedure codes. As you work as a health care analysts, your organization may have CPT codes yet it may not use them extensively. As a result, the CPT codes may not be available in some cases. In some, remember that CPT is a common representation for procedures, and there is often an overlap with ICD in this case. LOINC is the Logical Observation Identifiers Names and Codes maintained by the Regenstrief institute which is an Indianapolis based research organization, affiliated with Indiana University. Regenstrief maintains link and as a very useful helpful website linked.org to apply names and identifiers to over 71,000 laboratory medical terms. HL7 has identified LOINC as a preferred standard. We'll get to what HL7 means in the next lesson. In addition, LOINC along with SNOMED-CT helps to find medical concepts in the clinical document architecture which is a markup standard for HL7. LOINC is endorsed by the College of American pathologists and others. Harmonisation between LOINC and SNOMED-CT is ongoing. It's targeted to provide semantic interoperability between disparate laboratory systems, and it works well as a reference terminology for comparing data from different labs. The LOINC format is generally used to define medical laboratory procedures. These terms generally have numerous elements. There's the component, what you are measuring and what's being observed. Next there is the property or the characteristics of what is being measured. For example, there might be length, mass, or the volume. Moving on, what's the observation interval? When was this looked at? For how long? What is the context or what is the specimen type that's being addressed? What's the scale? What's the type of scale? Is it a quantitative or nominal term? What type of method or the procedure was used to actually collect the specimen? The codes themselves are much more cryptic looking in this, but the same information is contained in them. I do not have time to go into more details about LOINC. More detail on LOINC can be found at their LOINC.org website where you'll find what LOINC is and how it can be used. Now, we're going to briefly mentioned some terminologies that target drug vocabularies. There are a number of proprietary drug databases, thus there are a number of proprietary drug vocabularies. There's Multum, Micromedex, First Databank, Medi-Span, MedDRA as well as others. These are proprietary drug databases, and companies built these for specific purposes. Next, there are federal drug data initiatives such as NDC which is the National Drug Code were drug products are identified and reported using a unique three segment number. This is the three segment number that's available and all of your U.S. prescription bottles. The NDC directory is updated daily. So, new drugs are added in re-characterizing all the time RxNorm is a terminology that is a list of normalized names for clinical drugs. It takes all these proprietary drug databases in normalizes them to essential reference terminology so that you can map drug databases across one another. These proprietary systems and NDC codes can be mapped across their database. They are normalized names for clinical drugs that are mapped to the different drug databases, proprietary or otherwise. Wow! That was a quick summary to some of the important terminology systems. Clearly, you will have some work to do on your own to learn more, but I think this will get you started.
