New SI Version of the LOINC Top 2000+ Lab Observations

Regenstrief Institute and the LOINC Development Team are pleased to announce the availability of a new SI version of the user-favorite LOINC Top 2000+ Lab Observations list and mapper's guide.

download-32.pngDownload both the SI and US versions of the LOINC Top 2000+ at

The original Top 2000 was based on the reporting patterns of three large organizations in the United States. These laboratories commonly report in mass units, e.g. mg/dL, rather than molar units, e.g. mmol/L.  Since LOINC codes are in use by many countries that report various tests in molar units, we wanted to adapt this list for that context too. We are indebted to Dr. Gilbert Hill at The Hospital for Sick Children, Toronto, Ontario, Canada, for helping us create this SI version.

Dr. Hill identified tests within the Top 2000 that are typically reported in molar and/or mass units.  For those that are commonly reported in molar units in Canada, the equivalent mass term was replaced.  For those tests that are reported in either mass or molar units, the mass term remained and the molar term was added. You can read more about development of both the US and SI versions in the Introduction.

We hope hope you find this new resource helpful. As always, feedback is welcome.