Clinical Architecture Blog

Its Just a Simple Procedure...Current Procedure Terminology (CPT)The Current Procedural Terminology (CPT) code set is maintained by the American Medical Association through the CPT Editorial Panel. The CPT code set accurately describes medical, surgical, and diagnostic services and is designed to communicate uniform information about medical services and procedures among physicians, coders, patients, accreditation organizations, and payers for administrative, financial, and analytical purposes.All CPT Codes are 5 digits.

There are roughly 9200 CPT codes today.Here is an example of some CPT codes15788      CHEMICAL PEEL, FACIAL; EPIDERMAL15789      CHEMICAL PEEL, FACIAL; DERMAL15792      CHEMICAL PEEL, NONFACIAL; EPIDERMAL The code is not hierarchical but they do fall within defined numeric ranges calledsections.The use of CPT codes requires a license from the AMA.  The main CPT page on the AMA site is located here: http://www.ama-assn.org/ama/pub/physician-resources/solutions-managing-your-practice/coding-billing-insurance/cpt.shtmlThe Wikipedia page for CPT is located here:http://en.wikipedia.org/wiki/Current_Procedural_TerminologyThere is a good document covering the fundamentals of CPT coding here: http://pmiconline.com/ebook.pdfCPT codes are in the UMLS metathesaurus, but you are required to have a CPT license to use them.  

ICD-10-PCS

The International Classification of Diseases, Tenth Revision, Procedure Coding System (ICD-10-PCS) was developed as a replacement for the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) volume 3, Procedures.It is important to note that unlike the diagnosis and procedures subsets in ICD-9, ICD-10-CM and ICD-10-PCS are separate and distinct vocabularies.  They are not subsets of a holistic ICD-10.  This starts with the fact that the structure of a ICD-10-PCS code is not the same as a ICD-10-CM code.



ICD-10-PCS has a seven character alphanumeric code structure. Each character contains up to 34 possible values. Each value represents a specific option for the general character definition (e.g., stomach is one of the values for the body part character). The ten digits 0-9 and the 24 letters A-H,J-N and P-Z may be used in each character. The letters O and I are not used in order to avoid confusion with the digits 0 and 1.The second through seventh characters mean the same thing within each section, but may mean different things in other sections.In all sections, the third character specifies the general type of procedure per-formed (e.g., resection, transfusion, fluoroscopy), while the other characters give additional information such as the body part and approach. In ICD-10-PCS, the term "procedure" refers to the complete specification of the seven characters.I think the approach here is risky, primarily due to the limit of 34 items within each component of the smart key.  Many vocabularies have abandoned smart key system like this because of the complexity that is introduces when you need to add an item beyond the possible range (like #35…).

The reference manual for the ICD-10-PCS coding system can be downloaded here: https://www.cms.gov/ICD10/Downloads/pcs_refman.pdf

Wikipedia has a fairly robust ICD-10-PCS list and reference capability here: http://en.wikipedia.org/wiki/ICD-10_Procedure_Coding_System

You can download the latest ICD-10-PCS data files here:http://www.cms.gov/ICD10/13_2010_ICD10PCS.asp#TopOfPage
(The file you want is the ‘2010 Code Descriptions – Long format, Table format’ zip file.)

There are roughly 72,000 ICD-10-PCS Codes.According to the American college of Emergency Physicians (ACEP), some preliminary inpatient hospital testing of ICD-10-PCS has indicated that the new procedure coding system is problematic to learn for both experienced and inexperienced coders. If this is true, it may be that CPT-4, which is also an anointed vocabulary, would be a better choice for procedures.The next post will be about allergy vocabularies.

PLEASE NOTE: The Meaningful Use Final Rule was released on July 12 and the UNII is no longer listed as the standard for allergy terminology.  In fact, there is NO standard listed for allergy interoperability.  For the record, I do not think that the following blog post, which "aired" on June 30th, influenced the governments decision making process in any way.  My next post will suggest a significant stimluls for healthcare IT companies with the word 'architecture' in the name... just in case.  In order to preserve history, I am leaving the post as it was.  It still provides a decent overview of UNII for those of you that would like to leverage it.

The vocabulary chosen to represent patient allergies is the FDA Unique Ingredient Identifier or UNII (I guess ‘UII' would be a difficult acronym to use in casual conversation...).

The UNII is part of the Substance Registration System whose purpose is to provide unique identifiers for:

Foods

• Food substances are specific foods or components of food, regardless of whether the food is in conventional food form or a dietary supplement, such as vitamins, minerals, herbs, or other similar nutritional substances.

Drugs

• Drug substances include both active and inactive ingredients used in drug products, including those for veterinary purposes.

Biologics

• Biologic substances include both active and inactive ingredients used in biologics, such as blood products, therapeutic products, vaccines, cellular and gene therapy products, allergenic products, tissues, and certain devices (e.g., enzymes in stabilized solutions).

Devices

• Device substances include certain components of some devices (e.g. silicon for implants, and chemical reagents for glucose test kits).

Cosmetics

• Cosmetic substances are components of cosmetic products, such as flavors, fragrances, colorants, vitamins, plant- and animal-derived ingredients, and polymers.

 There is more general information on the UNII here: http://www.fda.gov/ForIndustry/DataStandards/SubstanceRegistrationSystem-UniqueIngredientIdentifierUNII/default.htm

According to the above site, the UNII is:

• One of the core components of the United States Federal Medication Terminology.
• Used in the FDA's Structured Product Labeling
• Used to assist in the generation of the National Library of Medicine's (NLM's) RxNorm.
• A US government standard for drug ingredient and food allergen identifiers
• A component of the Environmental Protection Agency's Substance Registry System (future)

The UNII may be found in:

• NLM's Unified Medical Language System (UMLS)
• National Cancer Institute's Enterprise Vocabulary Service
• USP Dictionary of USAN and International Drug Names (future)
• FDA Data Standards Council website
• VA National Drug File Reference Terminology (NDF-RT)
• FDA Inactive Ingredient Query Application

The UNII is provided, rather inconveniently, in excel format. 

There is a multi-worksheet (A-S, T-Z), denormalized, zipped excel workbook dated 6/25/2010 at the following location.

http://www.fda.gov/downloads/ForIndustry/DataStandards/StructuredProductLabeling/UCM217498.zip

The sheets are difficult to work with because they have combined the concepts and their synonyms into a single list.  It is also worth noting, that in the data provided the synonyms do not have unique identifiers.

Sheet Structure

The primary sheets with the UNII codes in them have the following columns:

Preferred substance name	This is the preferred name of the substance
UNII	The Unique identifier the preferred substance name
Substance name	A synonym for the preferred substance name
IT IS TSN	This is not really documented, BUT I believe it is, where applicable, a code representing the USDA Integrated Taxonomic Information System (ITIS) Taxanomic Serial Number (TSN).   This appear to only be populated for food ingredients
Molecular Formula	This is, you guessed it, the molecular formula.  It seems to only be populated for chemical ingredients.

Code structure and design

The UNII code is a ten character alpha-numeric code.  The first nine digits are randomly generated and the tenth digit is determined by an algorithm (a check digit for you old timers who wrote serial port interfaces...).

 The Numbers

There are 16,655 unique UNII concepts in the provided list.
There are 67,715 synonyms, including the preferred names.

What's missing?

UNII Type:             

We know that the scope of the UNIIs covers a number to types of substances.  It would be very useful if there was a way of telling which UNIIs are of which type so that we could filter them.  I may not want to include cosmetics OR biologics in my allergy pick list, for example.

Allergies:              

In most systems that track allergies, medication allergies in particular, they allow the user to represent allergies using medication ingredients, common brand names OR allergy classes.  The UNII scope only covers one of these.  How will we use UNII to represent and documented allergy or adverse reaction to ‘Nyquil' or ‘cephalosporins'?  Also, if you are going to represent allergies should the list include animals and environmental allergies.

Not a Rant

I don't want to get off on a rant here... but it seems like for some of these meaningful use terminologies, rather than creating a terminology designed to support appropriate interoperability, we looked to see what we already had lying around.  UNII is not an allergy terminology, it is a substance terminology. They are not the same thing.  They are terminology domains that merely overlap.  I know, creating a terminology is hard but, ahem, 19 billion dollars!  This is not a criticism directed at the UNII codes or the people that maintain them.  It looks like a very thorough substance terminology with a fairly simple design, but it will not support allergy interoperability as it should be supported.  Now, we could change UNII terminology to include allergy classes, animals and environmental terms, but that would make it a less wonderful substance terminology then, wouldn't it?  Perhaps a better approach would be to use UNII in our allergy interoperability terminology, in the utopian future, to represent substances (with types please) and we could append the other allergy types (classes, animals, environmental) to save money and reduce the deficit.  I could live with that.

 (I will now climb down from my virtual soap box, so that you can come out from behind your furniture...)
To make up for the non-rant, I am happy to provide a normalized version of the most recent UNII data for your experimentation.  It is provided in a zip file as two, pipe ‘|'delimited text files with the following structure.



If you would like to receive this file, contact us and ask for it.  We will email it to you or provide you with access to our FTP server. 

I want to thank Bonnie for reminding me that I should do this post.

I will try to post more frequently.