Hamilton Regional Laboratory Medicine Program (HRLMP), Hamilton, Ontario, Canada.
Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada.
Biochem Med (Zagreb). 2024 Oct 15;34(3):030703. doi: 10.11613/BM.2024.030703. Epub 2024 Aug 5.
Thyroid-stimulating hormone (TSH) is a glycoprotein secreted by the anterior pituitary gland and is regulated by negative feedback from the serum free thyroid hormones. In this study we aimed to quantitate the relative bias caused by calibration drifting as seen in our TSH Levey-Jennings quality control (QC) charts and assess the magnitude of bias on patients' samples.
In the period from October 2021 to August 2022 we looked at the QC results of ten 28-days' calibration time intervals and calculated relative bias compared to the mean. For each time interval the mean from three QC points before and after calibration was calculated. The average from 10 pre- and post-calibration means was calculated and the relative bias, pre- and post-calibration, was then calculated. We used 5 patient samples with low, normal and high TSH concentrations and calculated relative bias pre- and post-calibration. The allowed relative bias for TSH is ± 6.7%.
At both QC levels, with the respective means of 5.14 mIU/L (coefficient of variation, CV% = 3.1%) and 27.80 mIU/L (CV% = 3.2%) had their respective relative bias - 8.2% and - 7.9%. The patient samples with low (0.586 mIU/L), normal (2.89 mIU/L and 5.19 mIU/L) and high (20.5 mIU/L and 39.8 mIU/L) TSH had - 4.1%, - 4.0%, - 3.5%, - 5.1% and - 4.1%, respectively.
Even though the relative bias exceeded allowable criteria for the QC samples, this was not manifested on the patients' samples.
促甲状腺激素（TSH）是由垂体前叶分泌的糖蛋白，受血清游离甲状腺激素的负反馈调节。本研究旨在定量分析 TSH Levey-Jennings 质控（QC）图表中所见校准漂移引起的相对偏差，并评估其对患者样本的偏差程度。
在 2021 年 10 月至 2022 年 8 月期间，我们观察了十个 28 天校准时间间隔的 QC 结果，并计算了与平均值的相对偏差。对于每个时间间隔，我们计算了校准前后三个 QC 点的平均值。计算了 10 个校准前后平均值的平均值，并计算了校准前后的相对偏差。我们使用了 5 个 TSH 浓度低、正常和高的患者样本，并计算了校准前后的相对偏差。TSH 的允许相对偏差为±6.7%。
在 QC 水平 1 和 2 下，相应的均值为 5.14 mIU/L（变异系数，CV%=3.1%）和 27.80 mIU/L（CV%=3.2%），相对偏差分别为-8.2%和-7.9%。TSH 浓度低（0.586 mIU/L）、正常（2.89 mIU/L 和 5.19 mIU/L）和高（20.5 mIU/L 和 39.8 mIU/L）的患者样本的相对偏差分别为-4.1%、-4.0%、-3.5%、-5.1%和-4.1%。
尽管 QC 样本的相对偏差超过了允许标准，但这并未在患者样本中表现出来。
