考虑在就诊时将高敏肌钙蛋白值低于第 99 百分位作为参考：这是否能提高诊断准确性？
Consideration of high-sensitivity troponin values below the 99th percentile at presentation: does it improve diagnostic accuracy?
机构信息
Department of Cardiology, University Hospital, Basel, Switzerland; Paris XIII University, Cardiology Department, Avicenne Hospital, Bobigny, France; Paris Descartes University, Cardiology Department, Cochin Hospital, APHP, Paris, France.
出版信息
Int J Cardiol. 2013 Oct 9;168(4):3752-7. doi: 10.1016/j.ijcard.2013.06.011. Epub 2013 Jul 12.
BACKGROUND
The introduction of high-sensitivity cardiac troponin (hs-cTn) assays allows the assessment of clinical decision values below the 99th percentile.
METHODS
Final diagnosis and one-year mortality were adjudicated in a multicenter, prospective cohort of 1181 patients presenting with acute chest pain to the emergency department. Hs-cTnT (Roche) and cTnI-ultra (Siemens) were measured in a blinded fashion.
RESULTS
At presentation hs-cTnT and cTnI-ultra were below the limit of blank (LOB) in 201 (17%) and 549 (47%) patients, below the 75th percentile in 379 (32%) and 623 (53%) patients, below the 95th percentile in 603 (51%) and 808 (68%), and below the 99th percentile in 748 (63%) and 913 (77%), respectively. Sensitivities for the diagnosis of AMI were 100.0% and 96.8% respectively for hs-cTnT and cTnI-ultra (LOB as cut-off value), 99.5% and 96.2% (75th percentile), 96.8% and 93.0% (95th percentile), and 94.1% and 88.1% (99th percentile). The proportion of patients correctly classified as having or not AMI increased from 32.9% (LOB as cut-off value) to 47.8% (75th percentile), 65.9% (95th percentile) and 77.3% (99th percentile) for hs-cTnT and from 61.2% to 67.3%, 81.9% and 89.3% respectively for cTnI-ultra. At 1 year, all-cause mortality was very low and similar for patients below all of these cut-off levels (between 0.7% and 1.5%, p=0.748 for all-groups comparison).
CONCLUSION
cTn should be considered as a continuous variable. Decision values below the 99th percentile (e.g. the 75th percentile) are associated with a very high NPV for the diagnosis of AMI, but have a lower accuracy than the 99th percentile.
背景
高敏心肌肌钙蛋白（hs-cTn）检测方法的引入可评估 99 百分位以下的临床决策值。
方法
对 1181 例因急性胸痛就诊于急诊科的多中心前瞻性队列患者进行最终诊断和 1 年死亡率的评估。以盲法方式检测 hs-cTnT（罗氏）和 cTnI-ultra（西门子）。
结果
在就诊时，201 例（17%）和 549 例（47%）患者的 hs-cTnT 和 cTnI-ultra 低于检测限（BL），379 例（32%）和 623 例（53%）患者低于第 75 百分位，603 例（51%）和 808 例（68%）患者低于第 95 百分位，748 例（63%）和 913 例（77%）患者低于第 99 百分位。hs-cTnT 和 cTnI-ultra 的 AMI 诊断灵敏度分别为 100.0%和 96.8%（以 BL 为截断值），99.5%和 96.2%（第 75 百分位），96.8%和 93.0%（第 95 百分位），94.1%和 88.1%（第 99 百分位）。将患者正确分类为患有或不患有 AMI 的比例从 32.9%（以 BL 为截断值）增加到 47.8%（第 75 百分位）、65.9%（第 95 百分位）和 77.3%（第 99 百分位），hs-cTnT 从 61.2%增加到 67.3%，cTnI-ultra 从 81.9%增加到 89.3%。在 1 年时，所有原因的死亡率均非常低，且低于所有这些截断值的患者的死亡率相似（0.7%至 1.5%之间，所有组间比较 p=0.748）。
结论
cTn 应被视为连续变量。第 99 百分位以下（如第 75 百分位）的决策值与 AMI 的诊断具有非常高的阴性预测值，但准确性低于第 99 百分位。
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