Influence of Turkish origin on hematology reference intervals in the German population

Arndt Groening,Markus Metzler,Alexander Bertram,Alexander Krebs,Reinhard Hoffmann,Thomas Gscheidmeier,Hans-Jürgen Groß,Oliver Razum,Manfred Rauh,Holger Cario,Franz X Mayr,Stefanie Grützner,Joachim Woelfle,Jakob Zierk,Hans-Georg Ruf,Michael C Frühwald,Antje Torge

doi:10.1038/s41598-021-00566-2

Abstract

Reference intervals for laboratory test results have to be appropriate for the population in which they are used to be clinically useful. While sex and age are established partitioning criteria, patients’ origin also influences laboratory test results, but is not commonly considered when creating or applying reference intervals. In the German population, stratification for ethnicity is rarely performed, and no ethnicity-specific hematology reference intervals have been reported yet. In this retrospective study, we investigated whether specific reference intervals are warranted for the numerically largest group of non-German descent, individuals originating from Turkey. To this end, we analyzed 1,314,754 test results from 167,294 patients from six German centers. Using a name-based algorithm, 1.9% of patients were identified as originating from Turkey, in line with census data and the algorithm’s sensitivity. Reference intervals and their confidence intervals were calculated using an indirect data mining approach, and Turkish and non-Turkish reference limits overlapped completely or partially in nearly all analytes, regardless of age and sex, and only 5/144 (3.5%) subgroups’ reference limits showed no overlap. We therefore conclude that the current practice of using common reference intervals is appropriate and allows correct clinical decision-making in patients originating from Turkey.

Highlights

Originate from European countries outside the EU
In addition to environmental factors, genetic variation may affect laboratory test results, especially hematologic analytes, in individuals originating from Turkey: Several genetic diseases and traits, which include hemoglobinopathies and enzyme defects, such as alpha and beta thalassemia, sickle cell disease or glucose-6-phosphate dehydrogenase deficiency (G6PDD), lead to changes in hematologic parameters
No peer-reviewed studies have been published so far on hematologic reference intervals for individuals originating from Turkey living in Germany, this might adversely impact the interpretation of laboratory test results in these individuals

Summary

Introduction

Originate from European countries outside the EU. About 21.5% are of Asian origin, while the remaining part originates mainly from the African and American continent. In addition to environmental factors, genetic variation may affect laboratory test results, especially hematologic analytes, in individuals originating from Turkey: Several genetic diseases and traits, which include hemoglobinopathies and enzyme defects, such as alpha and beta thalassemia, sickle cell disease or glucose-6-phosphate dehydrogenase deficiency (G6PDD), lead to changes in hematologic parameters. These conditions have a substantially higher prevalence in Turkey or the Mediterranean region than in Central Europe, and due to migration, these conditions are becoming less regionally concentrated and their prevalence in Germany increases[13]. It is limited by ethical objections, especially when pediatric RIs are established, and it is restricted in geriatric patients due to the high prevalence of comorbidities in this group[18,19]

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