Sources of variation and establishment of Russian reference intervals for major hormones and tumor markers

Anna Ruzhanskaya,Anton Vasiliev,Kiyoshi Ichihara,Nina Vybornova,Svetlana Evgina,Vladimir Emanuel,Galina Agarkova,Irina Skibo,Colin Johnson

doi:10.1371/journal.pone.0234284

Abstract

A multicenter study was organized to explore sources of variation (SVs) of reference values (RVs) for 22 major immunochemistry analytes and to determine reference intervals (RIs) for the Russian population. According to IFCC Committee on Reference Intervals and Decision Limits (C-RIDL) protocol, 758 healthy volunteers were recruited in St. Petersburg, Moscow, and Yekaterinburg. Serum samples were tested for five tumor markers, 17 hormones and related tests by Beckman Coulter's UniCel DxI 800 immunochemistry analyzer. SVs were explored using multiple regression analysis and ANOVA. Standard deviation ratio (SDR) of 0.4 was used as primary guide for partitioning RIs by gender and age. SDR for between-city difference was <0.4 for all analytes. Secondary exclusion of individuals was done under the following conditions: for female sex-hormones, those with contraceptives (8%); for CA19-9, those supposed to have negative Lewis blood-group (10.5% males and 11.3% females); for insulin, those with BMI≥28 kg/m2 (31%); for the thyroid panel, those with anti-thyroid antibodies (10.3% males; 24.5% females), for CEA those with smoking habit (30% males and 16% females). Gender-specific RIs were required for all analytes except CA19-9, CA15-3, thyroid-related tests, parathyroid hormone, and insulin. Age-specific RIs were required for alpha-fetoprotein, CEA, all sex-hormones for females, FSH and progesterone for both sexes. RIs were generally derived by parametric method after Gaussian transformation using modified Box-Cox formula. Exceptions were growth hormone, estradiol for females in postmenopause, and progesterone for females in premenopause, for which nonparametric method was required due to bimodal distribution and/or insufficient detection limit. RIs for major hormones and tumor markers specific for the Russian population were derived based on the up-to-date internationally harmonized protocol by careful consideration of analyte-specific SVs.

Highlights

Each clinical laboratory is expected to establish its own reference intervals (RIs) as recommended in the IFCC/Clinical and Laboratory Standards Institute (CLSI) guideline (C28-A3) [1], but most laboratories in Russia use RIs provided by the reagent manufacturers
Secondary exclusion of individuals was done under the following conditions: for female sex-hormones, those with contraceptives (8%); for carbohydrate antigen 19–9 (CA19-9), those supposed to have negative Lewis blood-group (10.5% males and 11.3% females); for insulin, those with body mass index (BMI) 28 kg/m2 (31%); for the thyroid panel, those with anti-thyroid antibodies (10.3% males; 24.5% females), for carcinoembryonic antigen (CEA) those with smoking habit (30% males and 16% females)
Gender-specific RIs were required for all analytes except CA19-9, carbohydrate antigen 15–3 (CA15-3), thyroid-related tests, parathyroid hormone, and insulin

Summary

Introduction

Each clinical laboratory is expected to establish its own reference intervals (RIs) as recommended in the IFCC/CLSI guideline (C28-A3) [1], but most laboratories in Russia use RIs provided by the reagent manufacturers They may not match to the Russian population due to a variety of population-specific factors. The study revealed clear between-country differences for parathyroid hormone (PTH), adiponectin, folate, and vitamin B12 (VB12), but none for other analytes including most of commonly tested tumor markers and reproductive hormones. Another one is a Saudi Arabia study, conducted as a part of IFCC global multicenter study, where 826 apparently healthy individuals were recruited and RIs for 20 immunoassay analytes including five tumor markers, 12 hormones and three vitamins were derived [5]. No comprehensive analyses of biological sources of variations have been performed so far except for a recent report from a Chinese group collaborating in the C-RIDL global study, which established RIs for eight male sex hormone-related analytes and seven thyroid hormones and analyzedtheir SVs [10, 11]

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