Background

The determination of functional C1-INH is complex and depends on methodology, sample transport, and storage conditions. In clinical practice, we encounter individuals with pathological values which then cannot be proved true, and HAE patients in whom the values were wrongly found to be normal under non-optimum conditions. We aimed to test realistic real-life sample processing conditions for accurate C1-INH determination.

Methods

We conducted two national inter-laboratory comparisons with optimal sample preparation but different dispatch conditions. We also investigated variations of temperature and time, and their influence on C1-INH.

Results

C1-INH levels showed a significantly wider dispersion under suboptimal transport conditions than under optimal conditions (p < 0.00001). Two putatively healthy patient samples turned out to be pathological. Contrary to our expectations, we found no significant trend in a specific direction when the variables of temperature, time and sample material were combined and varied under realistic conditions. However, the range of variation in [%] functionality was markedly greater in supposedly healthy volunteers. Thus, under experimental conditions we obtained false pathological results that were not far from reality.

Conclusion

C1- INH determination is crucial for the diagnosis of HAE. Time, temperature, and sample handling have a significant impact on this laboratory value, sometimes leading to incorrect values, inaccurate diagnoses, and inappropriate therapies. This underlines the importance of proper handling of samples. If a patient has ambiguous C1-INH values despite optimized conditions, thus hindering a conclusive diagnosis of HAE, we recommend genetic testing.

中文翻译：

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C1-INH 测试在日常实验室工作中的关键

背景

功能性 C1-INH 的测定很复杂，取决于方法学、样品运输和储存条件。在临床实践中，我们会遇到具有病理值但无法证明为真的个体，以及在非最佳条件下错误地发现这些值是正常的 HAE 患者。我们旨在测试真实的样品处理条件，以准确测定 C1-INH。

方法

我们进行了两个国家实验室间比较，采用最佳样品制备但不同的调度条件。我们还研究了温度和时间的变化及其对 C1-INH 的影响。

结果

C1-INH 水平在次优运输条件下比在最佳条件下显示出明显更广泛的分散 ( p  < 0.00001)。两个假定健康的患者样本被证明是病理性的。与我们的预期相反，当温度、时间和样品材料等变量在现实条件下组合和变化时，我们没有发现特定方向上的显着趋势。然而，在假定健康的志愿者中，[%] 功能的变化范围明显更大。因此，在实验条件下，我们得到了与现实相去不远的错误病理结果。

结论

C1-INH 的测定对于 HAE 的诊断至关重要。时间、温度和样品处理对该实验室值有重大影响，有时会导致值不正确、诊断不准确和治疗不当。这强调了正确处理样品的重要性。如果患者在优化条件下仍具有不明确的 C1-INH 值，从而阻碍了 HAE 的结论性诊断，我们建议进行基因检测。