Laboratory Medicine ›› 2016, Vol. 31 ›› Issue (8): 635-639.DOI: 10.3969/j.issn.1673-8640.2016.08.001

• Orginal Article •     Next Articles

Matrix effect on serum uric acid determination

ZHANG Jiangtao, ZENG Jie, MA Rong, ZHAO Haijian, ZHOU Weiyan, ZHANG Tianjiao, YAN Ying, HU Cuihua, WANG Jing, WANG Donghuan, ZHANG Chuanbao   

  1. National Center for Clinical Laboratories,Beijing Hospital,Beijing 100730,China
  • Received:2015-09-02 Online:2016-08-31 Published:2016-09-01

Abstract:

Objective To evaluate the matrix effect of 21 samples (sera and processed materials) on 13 routine determination systems in serum uric acid determination. Methods Determinations were performed according to the health industry standard WS/T356-2011. Isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS)was used as comparison method,and 13 kinds of uric acid kits(enzymic assay) were chosen as evaluation method with HITACHI 7180 analyzer. The 21 samples included 4 calibrators,5 kinds of external quality assessment(EQA) samples,6 kinds of quality control materials,3 processed materials (1 kind of spine serum and 2 kinds of liquid solutions),1 kind of standard reference material(SRM) 909c from the National Institute of Standards and Technology (NIST)and 2 kinds of the External Quality Assessment Scheme for Reference Laboratories in Laboratory Medicine (RELA)samples from the International Federation of Clinical Chemistry and Laboratory Medicine(IFCC). A total of 40 fresh frozen sera and the 21 samples were analyzed by comparison method and evaluation method. The results obtained by the 2 methods were analyzed by linear regression analysis. Two-tailed 95% confidence intervals for Y predictive value were computed,and the matrix effect of sera and processed materials was evaluated. Results A total of 5 kinds of evaluation samples (2 EQA samples,1 SRM 909c and 2 RELA samples)from fresh or lyophilized sera showed no matrix effect in all routine methods. Two calibrators (Landau and Dirui) showed matrix effect in 1 routine method. Of 5 EQA samples,except for fresh sera used for trueness verification,other lyophilized sera showed matrix effect in most routine methods. The 4 of 6 quality control materials showed no matrix effect,and 2 quality control materials with high values showed negative matrix effect. Conclusions Fresh serum is a reliable sample and could be used in SRM and quality control material preparation and EQA. Some calibrators could introduce calibration bias due to matrix effect on non-matching routine methods. Thus,matrix effect evaluation and methodological verification are proposed prior to using non-matching calibrators.

Key words: Uric acid, Matrix effect, Enzymic assay, Isotope dilution, Liquid chromatography, Tandem mass spectrometry

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