Reference intervals for 12 clinical laboratory tests in a Danish population: The Lolland-Falster Health Study

Abstract

Reference intervals (RIs), developed as part of the Nordic Reference Interval Project 2000 (NORIP) are widely used in most European laboratories. We aimed to examine the validity of the NORIP RIs by establishing RIs for 12 frequently used laboratory tests based on data from a local Danish population and compare these local RIs with the NORIP RIs. Using an a posteriori direct sampling approach, blood sample data were assessed from 11,138 participants aged 18+ years in the Lolland-Falster Health Study (LOFUS), of whom 2154 turned out to meet criteria for being healthy for inclusion in establishing RIs according to the NORIP methodology. The 2.5th and 97.5th percentiles were calculated for alanine aminotransferase (ALAT), albumin, alkaline phosphatase, bilirubin, creatinine, hemoglobin, high-density lipoprotein cholesterol, iron, low-density lipoprotein cholesterol, thrombocytes, total cholesterol, and triglycerides. When comparing our estimates with the NORIP, the lower reference limits (RLs) for bilirubin and iron were lower, and higher for ALAT, thrombocytes and triglycerides. Upper RLs were lower for albumin (males and females ≥70 years), bilirubin and iron, but higher for alkaline phosphatase, triglycerides and for creatinine in men. In LOFUS, approximately 20% of the participants were healthy and qualified for inclusion in the establishment of RIs. Several of the local RIs differed from the NORIP RIs.

Keywords:

• Reference values
• biomarkers
• blood
• clinical chemistry tests
• humans
• Denmark

Acknowledgment

LOFUS is a collaboration between, Region Zealand, Nykøbing Falster Hospital, Lolland and Guldborgsund municipalities. The authors are grateful for permission to use the LOFUS data however, LOFUS bears no responsibility for the analysis or the interpretation conducted within this study. The authors thank the inhabitants of Lolland-Falster and the LOFUS staff for their commitment to the study. Thank you to Mads Skytte Rasmussen, Naestved Hospital for your help and support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data from the study can be made available via Region Zealand following the Danish Data Protection Regulation.

Additional information

Funding

This study was funded by Region Zealand.