Grunenberg R, Banik N, Krüger J
Institut für Transfusionsmedizin, Universität zu Köln, Deutschland.
Infusionsther Transfusionsmed. 1995 Jun;22(3):145-51.
The screening policy of alanine aminotransferase (ALT) testing in blood donors was reassessed. The cutoff value for ALT levels according to German guidelines has always been controversial. In this study the activity and distribution of ALT in a blood donor population were reevaluated and new exclusion levels were defined.
5,706 blood donors were tested for ALT activities with the Reflotron system at 37 degrees C. Donors with ALT levels > 51 IU/l were deferred, a detailed physical examination and additional serologic and biochemical testing were done.
ALT values of blood donors were transformed in logarithmic values in order to get a Gaussian distribution. The mean transformed value +/- SD was calculated with 1.24 +/- 0.14 for females and with 1.35 +/- 0.16 for males, corresponding to mean values of ALT activity of 17.6 and 22.5 IU/l, respectively. Exclusion levels of > 33.4 IU/l for female and > 46.7 IU/l for male blood donors (geometric mean +2.0 SD) predict a loss of donations of 2.8 and 2.7%, respectively, cutoff values of > 39.1 or > 56.1 IU/l (geometric mean +2.5 SD) a loss of 1.8 and 1.4%, respectively. The most likely causes of elevated ALT levels in 166 of our donors included daily alcohol use (82), infections with/without antibiotic medication (29), therapy with hepatotoxic drugs (8), strenuous exercises (5), bodybuilding complemented by anabolic steroids (2), acute infections with HCV (1), HBV (1) and CMV (1), alcohol/drug abuse and detection of HCV antibodies (1).
ALT screening is still considered a useful indicator of risk donors despite its nonspecificity and limited predictive value. The selection of the appropriate cutoff value has always been disputed. The present exclusion level of > 45 IU/l (25 degrees C), analogous to > 81.8 IU/l (37 degrees C), does not even take into account such a variable as sex. The cutoff value above 4.5 SD of the geometric mean for females and above 3.5 SD for males seems to be of limited medical and practical value.
对献血者丙氨酸氨基转移酶（ALT）检测的筛查政策进行了重新评估。根据德国指南，ALT水平的临界值一直存在争议。在本研究中，对献血人群中ALT的活性和分布进行了重新评估，并确定了新的排除标准。
使用Reflotron系统在37℃下对5706名献血者进行ALT活性检测。ALT水平>51 IU/l的献血者被延期献血，并进行详细的体格检查以及额外的血清学和生化检测。
将献血者的ALT值转换为对数值以获得高斯分布。计算得出女性转换后的平均值±标准差为1.24±0.14，男性为1.35±0.16，分别对应ALT活性平均值17.6和22.5 IU/l。女性献血者排除标准>33.4 IU/l，男性献血者排除标准>46.7 IU/l（几何平均值+2.0标准差），预计分别损失2.8%和2.7%的献血量；临界值>39.1或>56.1 IU/l（几何平均值+2.5标准差），预计分别损失1.8%和1.4%的献血量。在我们的166名献血者中，ALT水平升高的最可能原因包括每日饮酒（82例）、有/无抗生素治疗的感染（29例）、使用肝毒性药物治疗（8例）、剧烈运动（5例）、使用合成代谢类固醇辅助健身（2例）、急性丙型肝炎病毒（HCV）感染（1例）、乙型肝炎病毒（HBV）感染（1例）和巨细胞病毒（CMV）感染（1例）、酒精/药物滥用以及检测到HCV抗体（1例）。
尽管ALT筛查具有非特异性和有限的预测价值，但它仍然被认为是风险献血者的一个有用指标。合适临界值的选择一直存在争议。目前>45 IU/l（25℃）的排除标准，相当于>81.8 IU/l（37℃），甚至没有考虑性别等变量。女性高于几何平均值4.5标准差、男性高于3.5标准差的临界值似乎在医学和实际应用价值方面有限。
