Do you want to participate in a clinical study as a healthy control?-Risk or benefit?

A healthy woman volunteered to participate as "healthy control" in a study.An increased level of procalcitonin(PCT) was detected and remained elevated on follow-up measurements.As calcitonin levels were elevated as well,thyroid ultrasound was performed which revealed nodes in both thyroid lobes,one of them showing metabolic activity in positron emission tomography-computed tomography scan.To exclude a malignant thyroid cancer despite the negative findings in a fine needle aspiration the patient underwent thyroidectomy and a medullary thyroid carcinoma(MTC) was detected in the right lobe.MTC is a rare endocrine tumor with a poor prognosis once having spread,therefore early detection remains a priority for the outcome.Screening parameter is serum calcitonin,in absence of infection the pro-hormone PCT can be used as a screening parameter as well with high sensitivity.

监测降钙素原指导抗生素治疗

降钙素原（PCT）是一种可用于评估细菌感染可能性的生物学标志物。用PCT指导抗生素治疗是减少其滥用的一种新的手段，这有助于降低抗生素不良反应及多重耐药菌出现的风险。然而，对PCT水平的解读必须密切结合临床实际情况和检测方法的特性。在临床实践中，我们应使用敏感度较高的PCT检测方法，并根据临床实际情况确定具体的检测界值。现将PCT水平检测对指导不同临床表现和不同潜在感染患者抗生素治疗的优点和局限性概述如下。