Measurement of oxalate in the blood is essential for monitoring primary hyperoxaluria patients with progressive renal impairment and on dialysis prior to transplantation. As no external quality assurance scheme is available for this analyte, we conducted a sample exchange scheme between six laboratories specifically involved with the investigation of primary hyperoxaluria to compare results. The methodologies compared were gas chromatography/mass spectrometry (GCMS), ion chromatography with mass spectrometry (ICMS), and enzymatic methods using oxalate oxidase and spectrophotometry. Although individual laboratories performed well in terms of reproducibility and linearity, there was poor agreement (absolute values) between centres as illustrated by a longer-term comparison of patient results from two of the participating laboratories. This situation was only partly related to differences in calibration and mainly reflected the lower recoveries seen with the ultrafiltration of samples. These findings lead us to conclude that longitudinal monitoring of primary hyperoxaluria patients with deteriorating kidney function should be performed by a single consistent laboratory and the methodology used should always be defined. In addition, plasma oxalate concentrations reported in registry studies and those associated with the risk of systemic oxalosis in published studies need to be interpreted in light of the methodology used. A reference method and external quality assurance scheme for plasma oxalate analysis would be beneficial.

血液中草酸的测定对于监测具有进行性肾功能不全的原发性高草酸尿症患者以及移植前的透析至关重要。由于该分析物没有可用的外部质量保证方案，因此我们在六个专门从事原发性高草酸尿研究的实验室之间进行了样品交换方案，以比较结果。所比较的方法是气相色谱/质谱（GCMS），带质谱的离子色谱（ICMS）以及使用草酸氧化酶和分光光度法的酶促方法。尽管各个实验室在可重复性和线性方面均表现良好，但中心之间的一致性（绝对值）却很差，这可以从两个参与实验室的患者结果进行的长期比较中看出。这种情况仅部分与校准差异有关，并且主要反映了样品超滤后回收率较低。这些发现使我们得出结论，应由一个统一的实验室对肾功能恶化的原发性高草酸尿症患者进行纵向监测，并应始终确定所使用的方法。另外，在注册研究中报告的血浆草酸浓度以及在已发表的研究中与全身性草酸风险相关的血浆草酸浓度需要根据所使用的方法进行解释。血浆草酸盐分析的参考方法和外部质量保证方案将是有益的。这些发现使我们得出结论，应由一个统一的实验室对肾功能恶化的原发性高草酸尿症患者进行纵向监测，并应始终确定所使用的方法。另外，注册研究中报告的草酸血浆浓度以及已发表研究中与系统性草酸风险相关的血浆草酸浓度需要根据所用方法进行解释。血浆草酸盐分析的参考方法和外部质量保证方案将是有益的。这些发现使我们得出结论，应由一个统一的实验室对肾功能恶化的原发性高草酸尿症患者进行纵向监测，并且应始终定义所使用的方法。另外，注册研究中报告的草酸血浆浓度以及已发表研究中与系统性草酸风险相关的血浆草酸浓度需要根据所用方法进行解释。血浆草酸盐分析的参考方法和外部质量保证方案将是有益的。注册表研究中报告的血浆草酸浓度以及已发表研究中与系统性草酸风险相关的血浆草酸浓度需要根据所使用的方法进行解释。血浆草酸盐分析的参考方法和外部质量保证方案将是有益的。注册表研究中报告的血浆草酸浓度以及已发表研究中与系统性草酸风险相关的血浆草酸浓度需要根据使用的方法进行解释。血浆草酸盐分析的参考方法和外部质量保证方案将是有益的。