Detection of macroenzymes: establishing upper reference limits for eight enzymes after polyethylene glycol precipitation.

IF 3.8 3区医学 Q1 MEDICAL LABORATORY TECHNOLOGY

Biochemia Medica Pub Date : 2023-02-15 DOI:10.11613/BM.2023.010705

Lieselot Dedeene, Marie Stockman, Sophie Steels, Pieter Vermeersch, Glynis Frans

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引用次数: 0

Abstract

Introduction: The presence of macroenzymes in blood can cause diagnostic confusion. Therefore, confirming the presence of macroenzymes is important to reduce unnecessary (non-)invasive investigations. Polyethylene glycol (PEG) precipitation is a simple and fast first-line method for the detection of macroenzymes. However, there is no consensus on the upper reference limit for the PEG-precipitable activity (%PPA) of monomeric enzymes. The aim of this study was to verify a PEG precipitation protocol for the detection of macroenzymes in our laboratory by establishing upper reference limits (URLs) and determining imprecision for eight enzymes after PEG precipitation. In addition, we aimed to clinically verify the URLs using samples containing macroenzymes as identified by electrophoresis.

Materials and methods: Per enzyme, at least 40 leftover blood samples from adult patients with either normal or increased enzyme activities were diluted 1:1 with 25% PEG 6000 and 1:1 with 0.9% NaCl. Mixtures were incubated for 10 min at 37°C and centrifuged. Supernatant enzyme activity was measured on Cobas c702 and the %PPA was calculated.

Results: The following URLs were obtained: 26% PPA for amylase, 29% PPA for alkaline phosphatase (ALP), 61% PPA for alanine aminotransferase, 48% PPA for aspartate aminotransferase, 24% PPA for creatine kinase (CK), 55% PPA for gamma-glutamyltransferase, 65% PPA for lactate dehydrogenase, and 56% PPA for lipase. The within-lab imprecision was < 15%. Regarding the clinical verification, the two historical samples with proven macroCK showed a %PPA of 69% and 43%, respectively, and a sample with proven macroALP had a %PPA of 52%.

Conclusion: In this study, URLs for monomeric enzyme activities after PEG precipitation for eight different enzymes were established. The URLs are suitable for clinical use, but are only partially in line with other studies. Therefore, our data highlight the importance of establishing laboratory-specific upper reference limits for %PPA to allow a correct interpretation.

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大酶检测:聚乙二醇沉淀后建立8种酶的上参考值。

血液中巨酶的存在会导致诊断混乱。因此，确认大酶的存在对于减少不必要的(非)侵入性检查是很重要的。聚乙二醇(PEG)沉淀法是一种简便、快速的检测大型酶的一线方法。然而，对于单体酶的聚乙二醇可沉淀活性(%PPA)的参考上限尚无共识。本研究的目的是通过建立PEG沉淀后8种酶的上参考限(url)和测定不精确度，验证我们实验室中用于检测大型酶的PEG沉淀方案。此外，我们的目的是使用电泳鉴定的含有大酶的样品对url进行临床验证。材料和方法:每种酶，至少40份酶活性正常或升高的成年患者剩余血液样本，用25% PEG 6000 1:1稀释，0.9% NaCl 1:1稀释。混合物在37℃下孵育10分钟并离心。测定Cobas c702上清酶活性，计算PPA %。结果:获得了淀粉酶的26% PPA、碱性磷酸酶(ALP)的29% PPA、丙氨酸转氨酶的61% PPA、天冬氨酸转氨酶的48% PPA、肌酸激酶的24% PPA、γ -谷氨酰转移酶的55% PPA、乳酸脱氢酶的65% PPA、脂肪酶的56% PPA。实验室内不精确性< 15%。在临床验证方面，两个经证实的macroCK历史样品的PPA分别为69%和43%，经证实的macroALP样品的PPA为52%。结论:本研究建立了聚乙二醇沉淀后8种不同酶的单体酶活性url。url适合临床使用，但与其他研究只有部分一致。因此，我们的数据强调了建立实验室特定的%PPA上限的重要性，以允许正确的解释。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Biochemia Medica 医学-医学实验技术

CiteScore

5.50

自引率

3.00%

发文量

审稿时长

>12 weeks

期刊介绍： Biochemia Medica is the official peer-reviewed journal of the Croatian Society of Medical Biochemistry and Laboratory Medicine. Journal provides a wide coverage of research in all aspects of clinical chemistry and laboratory medicine. Following categories fit into the scope of the Journal: general clinical chemistry, haematology and haemostasis, molecular diagnostics and endocrinology. Development, validation and verification of analytical techniques and methods applicable to clinical chemistry and laboratory medicine are welcome as well as studies dealing with laboratory organization, automation and quality control. Journal publishes on a regular basis educative preanalytical case reports (Preanalytical mysteries), articles dealing with applied biostatistics (Lessons in biostatistics) and research integrity (Research integrity corner).