In this blog, we take a detailed look at LOINC Codes and SDTM. We look at several LOINC code examples and examine why it’s beneficial to use the codes alongside CDISC and NCI controlled terminology. We also include details of where to find the official LOINC codes list.
What are LOINC Codes used for?
Central Labs and other data providers may offer LOINC codes with their data transfer. Make sure this is included as a requirement in your Data Transfer Specification (DTS) document (the document that outlines the agreed collection method) as this will ensure the data is LOINC coded at source.
Important information about LOINC codes for SDTM
The CDISC knowledge base contains important information about LOINC and SDTM, including:
- While LOINC codes are NOT required by CDISC standards, there are benefits to using them
- LOINC codes have been an FDA requirement since March 2020
- As not all tests have LOINC terms, the FDA allow that codes may not be used in this case provided this is explained in the Study Data Reviews Guide (SDRG) and that some effort is made to obtain them.
LOINC code examples
LOINC code example - Glucose:
LOINC code example – CDISC SDTM Labs (LB) domain
First get the SDTM LBTESTCD/LBTEST string pair
Next, get the specimen type:
Example Lab (LB) output
LOINC code example – Lab Category (LBCAT)
LOINC code example – Lab Toxicity Grade (LBTOXGR)
LOINC Code Example – “Conventional Unit” to “SI Unit” conversion
Conversion table cont.
And using the equation below to calculate the normalized value:
Example of data cleaning process:
- Correct identification of measurement (Body Temperature).
- Uses the “unit” NCI code – not the collected text – which provides a “submission ready” unit.
- Allows different conversion factors for each measurement. For example, it is quite common for conversion factors to depend on specimen type or method.
- Provides full documentation of the normalization process (often requested for FDA submissions).
- Standardizes the process across all studies – but neutral to CDISC NCI SDTM terminology version, by using the NCI Code, not “unit” text.
Where to find the LOINC Codes list
Why use LOINC codes for STDM?
- Greater consistency
- Easier analysis and reporting
- More efficient, standardized process
About the author
Solutions Consultant | Formedix
Ed Chappell has been working as a Solutions Consultant with Formedix for over 15 years, and has 22 years’ experience in data programming. He authored and presents our training courses for SEND, SDTM, Define-XML, ODM-XML, Define-XML and Dataset-XML.
Ed was heavily involved in the development of our ryze dataset mapper, and works closely with customers on SDTM dataset mapping. As an expert in clinical data programming, Ed also supports customers with Interim Analysis (IA) SDTM and FDA SDTM clinical trial submissions.