Lazo Mariana, Selvin Elizabeth, Clark Jeanne M
Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205-2223, USA.
Ann Intern Med. 2008 Mar 4;148(5):348-52. doi: 10.7326/0003-4819-148-5-200803040-00005.
Clinicians sometimes order liver tests as part of a screening examination or general work-up. Current guidelines do not recommend routine retesting of abnormal results in asymptomatic patients.
To characterize the magnitude of intraindividual variability of liver test results and determine the proportion of adults with persistently elevated levels after 1 positive test.
Reliability study.
The NHANES (National Health and Nutrition Examination Survey) III First and Second Examinations (1988 to 1994).
1864 men and women age 18 years or older living in the United States.
Repeated measurements (mean, 17.5 days apart) of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, gamma-glutamyltransferase, and bilirubin.
Using NHANES III cutoffs for normal levels, 38% of adults with initially elevated bilirubin levels had normal levels at the second examination. These proportions were 36%, 31%, 17%, and 12% for AST, ALT, alkaline phosphatase, and gamma-glutamyltranferase, respectively. More than 95% of initially normal results remained normal. The results did not differ by alcohol consumption; hepatitis A, B, or C serologic status; recent infection; body mass index; or sociodemographic characteristics. Intraindividual variability was significantly higher for bilirubin (coefficient of variation, 23.4%) and ALT (coefficient of variation, 20.4%) than for AST (coefficient of variation, 13.9%), gamma-glutamyltransferase (coefficient of variation, 13.8%), and alkaline phosphatase (coefficient of variation, 6.7%).
Only 2 measurements were available. Complete liver disease history was lacking.
If retested, more than 30% of adults with elevated AST, ALT, or bilirubin levels would be reclassified as normal. Clinicians should be aware of the high intraindividual variability in common liver tests, and practice guidelines should explicitly recommend retesting of asymptomatic individuals with abnormal liver test results.
临床医生有时会将肝功能检查作为筛查或全面检查的一部分。目前的指南不建议对无症状患者的异常结果进行常规复查。
描述肝功能检查结果个体内变异性的程度，并确定首次检查结果为阳性后持续肝功能水平升高的成年人比例。
可靠性研究。
美国国家健康与营养检查调查（NHANES）III的第一次和第二次检查（1988年至1994年）。
1864名年龄在18岁及以上居住在美国的男性和女性。
重复测量天冬氨酸氨基转移酶（AST）、丙氨酸氨基转移酶（ALT）、碱性磷酸酶、γ-谷氨酰转移酶和胆红素（平均间隔17.5天）。
使用NHANES III的正常水平临界值，最初胆红素水平升高的成年人中，38%在第二次检查时胆红素水平正常。AST、ALT、碱性磷酸酶和γ-谷氨酰转移酶的这一比例分别为36%、31%、17%和12%。超过95%最初正常的结果仍保持正常。结果在饮酒情况、甲型、乙型或丙型肝炎血清学状态、近期感染、体重指数或社会人口统计学特征方面无差异。胆红素（变异系数23.4%）和ALT（变异系数20.4%）的个体内变异性显著高于AST（变异系数13.9%）、γ-谷氨酰转移酶（变异系数13.8%）和碱性磷酸酶（变异系数6.7%）。
仅有两次测量数据。缺乏完整的肝病病史。
如果进行复查，超过30%的AST、ALT或胆红素水平升高的成年人会被重新归类为正常。临床医生应意识到常见肝功能检查中个体内变异性较高，实践指南应明确建议对肝功能检查结果异常的无症状个体进行复查。
