Miyake Kazunori, Miyake Noriko, Kondo Shigemi, Tabe Yoko, Ohsaka Akimichi, Miida Takashi
Department of Clinical Laboratory Medicine, Juntendo University School of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo 113-8421, Japan.
Ann Clin Biochem. 2009 Sep;46(Pt 5):377-84. doi: 10.1258/acb.2009.008203. Epub 2009 Jul 29.
Long-term physiological variations, such as seasonal variations, affect the screening efficiency at medical checkups. This study examined the seasonal variation in liver function tests using recently described data-mining methods.
The 'latent reference values' of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyltransferase (gammaGT), cholinesterase (ChE) and total bilirubin (T-Bil) were extracted from a seven-year database of outpatients (aged 20-79 yr; comprising approximately 1,270,000 test results). After calculating the monthly means for each variable, the time-series data were separated into trend and seasonal components using a local regression model (Loess method). Then, a cosine function model (cosinor method) was applied to the seasonal component to determine the periodicity and fluctuation range. A two-year outpatient database (215,000 results) from another hospital was also analysed to confirm the reproducibility of these methods.
The serum levels of test results tended to increase in the winter. The increase in AST and ALT was about 6% in men and women, and was greater than that in ChE, ALP (in men and women) and gammaGT (in men). In contrast, T-Bil increased by 3.6% (men) and 5.0% (women) in the summer. The total protein and albumin concentrations did not change significantly. AST and ALT showed similar seasonal variation in both institutions in the comparative analysis.
The liver function tests were observed to show seasonal variations. These seasonal variations should therefore be taken into consideration when establishing either reference intervals or cut-off values, which are especially important regarding aminotransferases.
长期的生理变化，如季节变化，会影响体检时的筛查效率。本研究使用最近描述的数据挖掘方法研究了肝功能检查的季节变化。
从一个为期七年的门诊患者数据库（年龄20 - 79岁；包含约127万个检测结果）中提取天冬氨酸转氨酶（AST）、丙氨酸转氨酶（ALT）、碱性磷酸酶（ALP）、γ-谷氨酰转移酶（γGT）、胆碱酯酶（ChE）和总胆红素（T-Bil）的“潜在参考值”。计算每个变量的月均值后，使用局部回归模型（Loess方法）将时间序列数据分为趋势和季节成分。然后，将余弦函数模型（cosinor方法）应用于季节成分以确定周期性和波动范围。还分析了另一家医院的两年门诊数据库（21.5万个结果）以确认这些方法的可重复性。
检测结果的血清水平在冬季往往会升高。男性和女性的AST和ALT升高约6%，且高于ChE、ALP（男性和女性）和γGT（男性）。相比之下，T-Bil在夏季男性中升高3.6%，女性中升高5.0%。总蛋白和白蛋白浓度无显著变化。在比较分析中，两家机构的AST和ALT均表现出相似的季节变化。
观察到肝功能检查存在季节变化。因此，在建立参考区间或临界值时应考虑这些季节变化，这对于转氨酶尤为重要。
