The Hospital Information Systems (HIS) at different medical centers have grown up mostly in isolation from each other. Even when an HIS is installed by a national vendor, each individual hospital has tended to make its own customizations and to follow past conventions. This is changing and it is changing because there are a number of issues driving rapid improvements in inter-hospital communication. The Meaningful Use (MU) Act is major factor and one that has been helping to set the pace, but because improved communication lowers costs and improves the quality of care insurers and medical institutions have been moving in this direction for their own reasons as well.
The regulations and standards for Health Information Exchange (HIE) are evolving rapidly. The overall framework for HIE resides in the Consolidated Clinical Data Architecture (C-CDA) and HL7 messaging protocols. This has given hospitals a unified approach towards managing their communication channels between physicians, clinics, other hospitals and insurers but one problem limiting the usefulness of this has been the different nomenclature used by different institutions for the same pieces of information.
When databases are grown in isolation they tend to end up with labels for data elements that are idiosyncratic and unique to each medical center. There needs to be a way to resolve this Tower of Babel and that is what the Logical Observation Identifiers Names and Codes (LOINC) organization is doing.
The basic idea is simple, and that is to provide a single, unique code for all medical terms and test results. Given just how many terms and result names are in common use around the world this is in reality a monumental task and still a work in progress. Depending on how you want to measure it, probably around 90% of the most common PFT test result names and observations have a LOINC code.
If your PFT Lab has an HIS interface, test data is either stored as a complete report (usually in PDF format), or as individual elements (FVC, FEV1, TLC, DLCO etc.) and occasionally as both. Storing and distributing PFT results as a complete report simplifies the PFT Lab’s HIS interface and does meet the current minimum requirements for HIE but this is likely going to change. The reason for this is that once information is enclosed in a PDF file it cannot be searched and can only be read by a human. The need to perform searches on patient test results by clinicians, insurers, researchers and automated decision systems is eventually going to make interfaces composed of individual data elements mandatory, not just for PFT Labs but for all clinical departments.
This means that sooner or later your HIS will have to store PFT data as individual elements and this is when the LOINC codes will become important. This is also when your knowledge of your lab’s PFT results will help to make sure that your test data ends up with the right LOINC code and that they will make sense when somebody at a different institution tries to read the them.
The LOINC naming system is in some ways a simplistic answer to a complicated problem. For example, we are used to thinking about an FEV1 being performed pre-bronchodilator, post-bronchodilator, post-exercise or as a predicted or percent of predicted value. There are no modifiers for LOINC codes, so there has to be a separate LOINC code for each possible FEV1 value. This means that a lot of LOINC codes are needed to describe even simple PFT test results and that there are still gaps.
The LOINC organization cheerfully acknowledges this problem and makes the ability to submit labels for new LOINC codes easy. New code submissions go into a queue and eventually to a relevant committee. When approved by committee the new code will be added to the next LOINC database update, which come out at regular intervals.
The LOINC database and its associated software RELMA (Regenstrief Institute LOINC Mapping Assistant) can be downloaded for free from the LOINC website. Unfortunately, RELMA is only available for Windows PCs but a CSV file of the database can be downloaded for OS X and Linux computers. The current download zip file for Windows PCs which includes the database and RELMA software is about 370 megabytes.
The need for HIE has also exposed some deficiencies in my PFT Lab’s database. There are a number of tests we perform on a more or less regular basis (6-minute walk, walking oximetry and HAST for example) that can only be entered as text values in the patient’s test notes. There is no place for these results in the database we got from the lab’s equipment vendor and I am not sure how widespread this problem is for other vendor’s databases but I suspect it is a common one. There are LOINC codes for some of these values, but at the moment there is no way to associate them with the actual test results. At the moment any solution we can come up with will be very idiosyncratic and unique to my lab. The databases that all PFT labs get from our equipment vendors are probably the single place we use store all our test results, even when they are not performed using the vendor’s equipment. For this reason I would like to see all of the PFT equipment vendors realize the need for a more comprehensive solution to a PFT Lab’s needs and provide more universal ways of entering these orphan test results.
If (when) your hospital is involved in HIE then your IT department will probably be aware of LOINC codes. Applying them correctly may be a separate issue and I would strongly recommend that all PFT Lab managers be proactive about this problem, both for the need to store PFT test results in their HIS as individual data items and in the need for their associated LOINC codes.
I’ve spent some time searching the LOINC database for PFT Lab-related codes and have placed what I’ve found into a spreadsheet. Feel free to download the Excel version or the LibreOffice version but be aware that I selected codes based on the needs of my PFT Lab and there may well be codes your lab needs that mine doesn’t. Also be aware that in many cases there are multiple LOINC codes for what appears to be the same value so in some cases you’ll just have to take your best guess at what the right one is.
Excel spreadsheet of LOINC PFT Codes
LibreOffice Spreadsheet of LOINC PFT Codes
The opportunities for improved medical care that will come from universal adoption of HIE by all medical centers, clinics, doctor’s offices and researchers are quite exciting and long overdue. The technology necessary for HIE has been around for decades but the costs involved in implementing it as well as a healthy dose of institutional inertia and the NIH (not invented here) syndrome have slowed its adoption. The benefits now greatly outweigh the costs and we need to make sure our PFT Labs will be part of this evolutionary step in information management.
Kudos to the people involved in LOINC, C-CDA, HL7, MU2 and their associated committees and organizations. This is difficult work far from the public eye and very much not the “sexy” part of medicine, and yet it is probably going be responsible for some of the biggest improvements in medical care we will see in the coming decade.
Links:
LOINC:
Meaningful Use:
http://www.cms.gov/Regulations-and-Guidance/Legislation
http://www.himss.org/meaningfuluse?navItemNumber=13303
C-CDA/HL7:
http://hl7book.net/Whitepapers
http://wiki.siframework.org/Companion+Guide+to+Consolidated+CDA+for+MU2
PFT Blog by Richard Johnston is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.