Franeková Janka, Bláha Martin, Bělohoubek Jiří, Kotrbatá Markéta, Sečník Peter, Kubíček Zdenek, Kettner Jiří, Jabor Antonín
Department of Laboratory Methods, Institute for Clinical and Experimental Medicine, Vídeňská 1958/9, 140 21 Prague 4, Czech Republic; Charles University, 3rd Faculty of Medicine, Ruská 87, 100 00 Prague 10, Czech Republic.
Department of Cardiology, Institute for Clinical and Experimental Medicine, Vídeňská 1958/9, 140 21 Prague 4, Czech Republic.
Clin Chim Acta. 2015 Jun 15;446:128-31. doi: 10.1016/j.cca.2015.03.046. Epub 2015 Apr 17.
Careful interpretation of discordant results in high-sensitivity troponin measurements is necessary in cases of suspect immunoassay interferences. We describe several procedures taken in a case of a polymorbid patient with chest pain, without clear evidence of myocardial necrosis and with increased high-sensitivity cardiac troponin T (hs-cTnT). We checked the Vafaie's algorithm for the evaluation of suspect interference in troponin measurements.
We conducted a case report analysis, additional measurements, a dilution test and pretreatment of plasma with blocking agents.
Concentration of hs-cTnT (99 th percentile of "healthy" population 14 ng/L) increased from 120.1 ng/L to 280.4 ng/L during an 8-month period and decreased to 216.3 ng/L during the following month with repeatedly negative troponin I (TnI), hs-cTnI, myoglobin and creatine kinase MB (CK-MB). Suspected false positivity of hs-cTnT was further confirmed by treatment of plasma with an antiheterophile blocking agent (hs-cTnT before treatment 280.4 ng/L, after 16.53/16.23 ng/L). This outcome was further confirmed by the manufacturer's experiments.
The false-positive results of hs-cTnT were caused by the presence of extremely rare high molecular weight protein, presumably IgM, most likely HAMA (human anti-mouse antibody). Only the pre-treatment of plasma with a blocking agent provided a reliable indication of the interference. Cooperation among clinicians, laboratory personnel and the manufacturer is essential.
在怀疑免疫测定干扰的情况下，仔细解读高敏肌钙蛋白测量结果中的不一致结果是必要的。我们描述了一名患有多种疾病且胸痛的患者所采取的几种程序，该患者没有明确的心肌坏死证据，但高敏心肌肌钙蛋白T（hs-cTnT）升高。我们检查了Vafaie评估肌钙蛋白测量中可疑干扰的算法。
我们进行了病例报告分析、额外测量、稀释试验以及用封闭剂对血浆进行预处理。
hs-cTnT浓度（“健康”人群第99百分位数为14 ng/L）在8个月内从120.1 ng/L升至280.4 ng/L，随后一个月降至216.3 ng/L，而肌钙蛋白I（TnI）、hs-cTnI、肌红蛋白和肌酸激酶同工酶MB（CK-MB）多次呈阴性。用抗嗜异性封闭剂处理血浆进一步证实了hs-cTnT的疑似假阳性（处理前hs-cTnT为280.4 ng/L，处理后为16.53/16.23 ng/L）。制造商的实验进一步证实了这一结果。
hs-cTnT的假阳性结果是由极罕见的高分子量蛋白（可能是IgM，很可能是人类抗小鼠抗体）的存在引起的。只有用封闭剂对血浆进行预处理才能可靠地指示干扰情况。临床医生、实验室人员和制造商之间的合作至关重要。
