title: Negative predictive value of procalcitonin in medullary thyroid carcinoma.
abstract: Calcitonin (CT), the major biochemical marker in medullary thyroid carcinoma (MTC) is prone to in vitro instability and suffers from scarcity of clinical laboratory platforms. Procalcitonin (PCT), the precursor of CT, free of these shortcomings, has been reported as a potential MTC marker. The aim of this study was to assess the negative predictive value (NPV) of PCT as a first-line marker in MTC. 476 serum samples referred to our laboratory for CT measurements were analyzed for PCT. NPVs of PCT were assessed at 3 cut-offs (0.05, 0.10 and 0.15 ng/mL) and the diagnosis of MTC was based on CT levels. PCT and CT levels were correlated (r=0.7554 for CT levels above 10 pg/mL, n=66). Accepting the CT cut-off based on the upper reference limit the NPV of PCT were 98.1% (0.05 ng/mL), 96.3% (0.10 ng/mL) and 95.4% (0.15 ng/mL) respectively. For a CT cut-off of 100 pg/mL the NPVs of PCT were 100% for all PCT thresholds. Serum PCT has a strong NPV and could be a good candidate for a first-line screening test to exclude MTC in patients with suspicious thyroid nodules or suggestive symptoms. Larger prospective studies are necessary to confirm our results.
authors.affiliation: Laboratoire de biochimie et Laboratoire d'hormonologie, Pôle de biologie médicale et pathologie, Hôpitaux Universitaires Est Parisien, Site Saint-Antoine, AP-HP, Paris, France.
authors.forename: Soo Kyung
authors.initials: SK
authors.lastname: Lim
authors.affiliation: Laboratoire de biochimie et Laboratoire d'hormonologie, Pôle de biologie médicale et pathologie, Hôpitaux Universitaires Est Parisien, Site Saint-Antoine, AP-HP, Paris, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Guéchot
authors.affiliation: Laboratoire de biochimie et Laboratoire d'hormonologie, Pôle de biologie médicale et pathologie, Hôpitaux Universitaires Est Parisien, Site Saint-Antoine, AP-HP, Paris, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Vaubourdolle
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood*; D002116:Calcitonin / Q000097:blood*; D018278:Carcinoma, Neuroendocrine / Q000097:blood* / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D013964:Thyroid Neoplasms / Q000097:blood* / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D002116:Calcitonin
keywords: calcitonin; medullary thyroid carcinoma; negative predictive value; procalcitonin