Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska University Hospital at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Clin Chem. 2012 Mar;58(3):628-37. doi: 10.1373/clinchem.2011.171496. Epub 2012 Jan 18.
High-sensitivity cardiac troponin T (cTnT) assays detect small clinically important myocardial infarctions (MI) but also yield higher rates of false-positive results owing to increased concentrations sometimes present in patients without MI. Better understanding is needed of factors influencing the 99th percentile of cTnT concentrations across populations and the frequency of changes in cTnT concentrations >20% often used in combination with increased cTnT concentrations for diagnosis of MI.
cTnT percentiles were determined by use of the Elecsys® hscTnT immunoassay (Modular® Analytics E170) in a random population sample, in emergency room (ER) patients, and in patients with non-ST-elevation MI (NSTEMI). Changes in cTnT concentrations were determined in hospitalized patients without MI.
The 99th cTnT percentile in a random population sample (median age, 65 years) was 24 ng/L. In ER patients <65 years old without obvious conditions that increase cTnT, the 99th cTnT percentile was 12 ng/L with little age dependence, whereas in those >65 years old it was 82 ng/L and highly age dependent. In hospitalized patients without MI the 97.5th percentile for change in the cTnT concentration was 51%-67%. cTnT remained below the 99th percentile (12 ng/L) in 1% of patients with NSTEMI until 8.5 h after symptom onset and 6 h after ER arrival.
Age >65 years was the dominant factor associated with increased cTnT in ER patients. This age association was more prominent in ER patients than in a random population sample. Changes in serial cTnT concentrations >20% were common in hospitalized patients without MI.
高敏心肌肌钙蛋白 T（cTnT）检测法可检测到较小的临床重要心肌梗死（MI），但由于 MI 患者中有时存在浓度升高的情况，也会导致更高的假阳性率。需要更好地了解影响人群中 cTnT 浓度第 99 百分位数的因素，以及常与 cTnT 浓度升高结合使用的 cTnT 浓度 >20%变化的频率，这些变化常用于 MI 的诊断。
使用 Elecsys® hscTnT 免疫分析法（Modular® Analytics E170）在随机人群样本、急诊室（ER）患者和非 ST 段抬高型心肌梗死（NSTEMI）患者中确定 cTnT 百分位数。在无 MI 的住院患者中确定 cTnT 浓度的变化。
随机人群样本（中位年龄 65 岁）中第 99 个 cTnT 百分位数为 24 ng/L。在年龄<65 岁且无明显增加 cTnT 的情况下的 ER 患者中，第 99 个 cTnT 百分位数为 12 ng/L，与年龄的相关性较小，而年龄>65 岁的患者为 82 ng/L，与年龄的相关性很大。在无 MI 的住院患者中，cTnT 浓度变化的第 97.5 百分位数为 51%-67%。在症状发作后 8.5 小时和 ER 到达后 6 小时，1%的 NSTEMI 患者的 cTnT 仍低于第 99 百分位数（12 ng/L）。
ER 患者中年龄>65 岁是与 cTnT 升高相关的主要因素。这种年龄相关性在 ER 患者中比在随机人群样本中更为明显。无 MI 的住院患者中 cTnT 浓度变化>20%的情况很常见。
