Background Children require reference intervals distinct from adults and, based on their unique developing physiology, several intervals are often required to accurately reflect the distribution of expected results in a healthy pediatric population. The establishment of pediatric reference intervals has proven challenging. While consenting adults volunteer to contribute their biological material towards the development of a reference interval, well children usually do not have the occasion to get blood drawn and the smaller the child, the more significant the impact of phlebotomy. For these reasons, scientists have sought out other methods for determining pediatric reference intervals. As an alternative, indirect statistical methods may be applied to large data sets of laboratory test results to ascertain a reference interval. The Multi-Modal Decomposition (MMD) is an iterative indirect method that decomposes a mixture of multiple normal distributions into separate components using the expectation-maximization (EM) algorithm The objective of the current study, was to apply MMD to ascertain reference intervals for free T4 in infants. Methods The study population included infants ranging in age from 1 day to 60 days who had specimens submitted for free T4 testing involving equilibrium dialysis followed by LC-MS/MS in a commercial reference laboratory (Quest Diagnostics Nichols Institute, San Juan Capistrano, CA). MMD was performed on 25,271 de-identified free T4 results to establish the reference intervals that were validated by comparison against free T4 values obtained on 238 de-identified specimens submitted for acylcarnitine testing, the specimen were analyzed for TSH and only the in-range specimens were include for Free T4 reference interval analysis. Results MMD analysis demonstrated distinct reference intervals for the following ages: 0 to 6 days (1.8 - 6.1 ng/dL), 7 days to <2 weeks (1 - 4.4 ng/dL), 2 to <3 weeks (0.8 - 3.5 ng/dL), 3 to <4 weeks (0.8 - 3 ng/dL), and 4 to <8 weeks (0.7 - 2.8 ng/dL). The data did not support the use of separate intervals for male and female children. Conclusions MMD analysis demonstrated distinct reference intervals for the following ages: 0 to 6 days (1.8 - 6.1 ng/dL), 7 days to <2 weeks (1 - 4.4 ng/dL), 2 to <3 weeks (0.8 - 3.5 ng/dL), 3 to <4 weeks (0.8 - 3 ng/dL), and 4 to <8 weeks (0.7 - 2.8 ng/dL). The data did not support the use of separate intervals for male and female children.

中文翻译：

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A-082 通过间接方法建立婴儿游离T4参考区间


背景 儿童需要与成人不同的参考区间，并且根据其独特的发育生理学，通​​常需要多个区间才能准确反映健康儿科人群中预期结果的分布。事实证明，建立儿科参考区间具有挑战性。虽然同意的成年人自愿为参考区间的制定贡献他们的生物材料，但健康的儿童通常没有机会抽血，而且儿童越小，放血的影响就越显着。由于这些原因，科学家们寻找了其他方法来确定儿科参考区间。作为替代方案，可以将间接统计方法应用于实验室测试结果的大数据集以确定参考区间。多模态分解 (MMD) 是一种迭代间接方法，使用期望最大化 (EM) 算法将多个正态分布的混合分解为单独的分量。当前研究的目标是应用 MMD 来免费确定参考区间婴儿中的 T4。方法 研究人群包括年龄从 1 天到 60 天不等的婴儿，这些婴儿的样本提交用于免费 T4 测试，涉及平衡透析，然后在商业参考实验室（Quest Diagnostics Nichols Institute，圣胡安卡皮斯特拉诺，加利福尼亚州）进行 LC-MS/MS 。对 25,271 个去识别的游离 T4 结果进行 MMD，以建立参考区间，通过与提交用于酰基肉碱测试的 238 个去识别的样本获得的游离 T4 值进行比较来验证该参考区间，对样本进行 TSH 分析，并且仅对范围内的样本进行分析包括用于免费 T4 参考区间分析。 结果 MMD 分析表明以下年龄有不同的参考区间：0 至 6 天 (1.8 - 6.1 ng/dL)、7 天至 <2 周 (1 - 4.4 ng/dL)、2 至 <3 周 (0.8 - 3.5 ng/dL) /dL)、3 至 <4 周 (0.8 - 3 ng/dL) 和 4 至 <8 周 (0.7 - 2.8 ng/dL)。数据不支持对男女儿童使用不同的时间间隔。结论 MMD 分析表明以下年龄有不同的参考区间：0 至 6 天 (1.8 - 6.1 ng/dL)、7 天至 <2 周 (1 - 4.4 ng/dL)、2 至 <3 周 (0.8 - 3.5 ng/dL) /dL)、3 至 <4 周 (0.8 - 3 ng/dL) 和 4 至 <8 周 (0.7 - 2.8 ng/dL)。数据不支持对男女儿童使用不同的时间间隔。