LOINC Mapping Services
Halfpenny Technologies offers LOINC Code mapping as one of our test dictionary management services. Our medical technologists routinely map test codes and test names from one system to the corresponding test code and test name in a second or even a third system. With basic test directory information provided by our clients this expertise allows us to accurately map legacy test codes to a LOINC Code.
Logical Observation Identifiers Names and Codes – LOINC – is a dataset that universally identifies clinical laboratory tests. The LOINC database was created by the non-profit Regenstrief Institute at Indiana University in 1994 when clinical laboratories were in the early stages of transmitting test results to hospitals, physician offices and payers. In addition to requiring that an interface be established between the sending and receiving computer systems it is necessary to "link" or "match" the tests in one system to their corresponding counterparts in the other system.
Due to inherent discrepancies in how tests are set up in legacy systems it is difficult to link tests in two separate test dictionaries. Note in the table below that one cannot use the test name or test code to link the tests because more information is required before an identical match can be determined.
The CPT4, which the laboratory industry routinely uses to identify a test, may not discriminate between two tests as shown in the chart below because both random and 24 hr urine tests have the same CPT4.
It may also be important to know the test method in order to assure that the tests are identical because different methodologies could report out different result values and/or report units.
The LOINC database includes a compilation of all of the different characteristics of a clinical laboratory test. It differentiates each test by component, property being measured (concentration, enzyme activity, etc.), timing, specimen type, type of measurement (qualitative, quantitative, nominal, narrative, etc.), methodology and other information.
Since each LOINC code represents a specific combination of attributes it is possible to positively identify each test. If all tests in each test directory for the entities listed in this table were identified by a LOINC code it would greatly facilitate communication of data between all of the systems because you could easily associate "apples with apples" and "oranges with oranges".
| Lab A | Lab B | Lab C | Physician Office A | Physician Office B | |
| Test Name | Chloride 24 Hour Urine | Chloride 24 Hr | Chloride, 24Ur | Chloride Urine | Urine Chloride |
| Test Code | CL24 | CLCU | 8944.671 | GLUU | URGLU |
| Specimen Type | 24 Hour Urine | 24 Hour Urine | 24 Hour Urine | Random Urine | Random Urine |
| CPT4 | 82436 | 82436 | 82436 | 82436 | 82436 |
| Units of Measure | mmol/L | MmolL/24hr | mEq/L | mmol/L | mmol/L |
| LOINC Code | 21194-6 | 2079-2 | 21194-6 | 2078-4 | 2078-4 |
There are 2,667 CPT4 codes for laboratory and pathology. However, there are almost 40,000 laboratory LOINC codes. These numbers alone indicate the degree of specificity in the LOINC database.
Halfpenny Technologies offers the expertise and technology to evaluate a test dictionary and associate a LOINC code with each test.
The process for mapping a test dictionary is tedious work and requires familiarity with the LOINC database. Our experienced personnel will review the client test dictionary. Please note the specific requirements listed below. We will map as many tests as possible to a LOINC code. Other tests will require additional information from the client laboratory staff. Subsequent follow-up calls with clients are necessary in order to obtain the information needed to enable the selection of the correct LOINC code for those difficult to code tests.
An individual test dictionary may take from several hours to a few weeks to complete a LOINC project. The complexity of the testing being performed in the laboratory is a leading factor for LOINC coding. Laboratories that perform highly complex testing will require a greater degree of interaction with the client laboratory to determine the proper LOINC codes. The preparation and input by the client laboratory’s technical staff is key to an effective LOINC transformation.
Occasionally some testing performed by the client laboratory does not match to existing LOINC codes. Halfpenny provides the documentation to the client for the request of a new LOINC code. Please note that Regenstrief charges nothing for the use of the LOINC database; additionally, the request for new codes is also free. The turnaround time to receive these new codes is highly variable.
Test Dictionary Requirements
- LIS Test Code
- LIS Test Name
- Alias and/or Abbreviation
- Units of Measure
- Test Type
- Orderable
- Resultable
- Profiles with their associated components
- Container
- Specimen Type
- Methodology
Note that this file can be provided in an electronic format such as Microsoft Excel or a text file.
Note: There are 2,667 CPT4 codes for laboratory and pathology. However, there are almost 40,000 laboratory LOINC codes. These numbers alone indicate the degree of specificity in the LOINC database.
The benefits of LOINC Code mapping, which Halfpenny can provide, include reduced errors, improved communication in integrated healthcare delivery networks, improved EHR (electronic health records), automatic transfer to public health authorities of case reports for reportable diseases, and improved transfer of payment information.