Abstract

Objective

A recent report from the Faroe Islands suggested mild iodine deficiency among women aged 40 years and older. New preliminary results showed an average urinary iodine concentration of 457 µg/L. This spurious finding encouraged the present report.

Methods

A subset of 17 consecutive pregnant women from an ongoing study provided an additional morning spot urine sample; one part was tested for a few seconds with a test strip for glucose, protein, and erythrocytes, and the other was left untouched. The women recorded the previous week’s intake of iodine-rich foods. Additionally, 12 tap water samples were collected such that three samples were sealed immediately, the remaining were strip tested for 10, 30 and 60 s, respectively. Urine and water samples were analysed using the ceri/arsen method after alkaline ashing.

Results

Median urinary iodine concentration (UIC) in pristine urine samples was 116 µg/L (IQR 79–204 µg/L; range 26–475 µg/L), and positively associated with iodine-rich food intake. UIC increase with test-strip dip varied from 10 to 94 times the non-dip value. In tap water, the pristine samples had an iodine concentration of 2–4 µg/L, which increased to 10,000 µg/L after 60 s.

Conclusion

Urine samples exposed to test strips can be contaminated within a few seconds leading to unreliable iodine results. Therefore, it is crucial that the study protocol clearly states the procedure for urine sample collection and handling, strict adherence to protocol, and that utensils used are dedicated to collecting urine to measure iodine.

中文翻译：

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尿液试纸和碘污染：碘营养调查中的一个棘手技巧

摘要

客观的

法罗群岛最近的一份报告表明，40 岁及以上的女性存在轻度碘缺乏症。新的初步结果显示平均尿碘浓度为 457 µg/L。这一虚假的发现鼓励了本报告。

方法

来自正在进行的研究的 17 名连续孕妇的子集提供了额外的晨尿样本；一部分用葡萄糖、蛋白质和红细胞的试纸测试了几秒钟，另一部分则保持不变。这些妇女记录了前一周摄入的富含碘的食物。此外，采集了 12 个自来水样品，其中三个样品立即密封，其余样品分别进行 10、30 和 60 秒的条带测试。在碱灰化后使用ceri/arsen方法分析尿液和水样。

结果

原始尿液样本中的中位尿碘浓度 (UIC) 为 116 µg/L（IQR 79–204 µg/L；范围 26–475 µg/L），与富含碘的食物摄入呈正相关。UIC 随试纸倾角的增加从非倾角值的 10 到 94 倍不等。在自来水中，原始样品的碘浓度为 2–4 µg/L，60 秒后增加到 10,000 µg/L。

结论

暴露于试纸的尿液样本可能会在几秒钟内被污染，从而导致碘检测结果不可靠。因此，研究方案必须清楚地说明尿液样本收集和处理的程序，严格遵守方案，并且使用的器具专用于收集尿液以测量碘。