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Clin Endocrinol (Oxf). 2013 Mar;78(3):358-64. doi: 10.1111/cen.12001.

Is basal ultrasensitive measurement of calcitonin capable of substituting for the pentagastrin-stimulation test?

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Hospices Civils de Lyon et Université Lyon 1, Centre de Médecine Nucléaire, Centre d'Investigation Clinique et Fédération d'Endocrinologie, Groupement Hospitalier Est, Centre de Recherche en Neurosciences, Lyon, France.



To evaluate a second-generation assay for basal serum calcitonin (CT) measurements compared with the pentagastrin-stimulation test for the diagnosis of inherited medullary thyroid carcinoma (MTC) and the follow-up of patients with MTC after surgery. Recent American Thyroid Association recommendations suggest the use of basal CT alone to diagnose and assess follow-up of MTC as the pentagastrin (Pg) test is unavailable in many countries.


Multicentric prospective study.


A total of 162 patients with basal CT <10 ng/l were included: 54 asymptomatic patients harboured noncysteine 'rearranged during transfection' (RET) proto-oncogene mutations and 108 patients had entered follow-up of MTC after surgery.


All patients underwent basal and Pg-stimulated CT measurements using a second-generation assay with 5-ng/l functional sensitivity.


Ninety-five per cent of patients with basal CT ≥ 5 ng/l and 25% of patients with basal CT <5 ng/l had a positive Pg-stimulation test (Pg CT >10 ng/l). Compared with the reference Pg test, basal CT ≥ 5 ng/l had 99% specificity, a 95%-positive predictive value but only 35% sensitivity (P < 0.0001). Overall, there were 31% less false-negative results using a 5-ng/l threshold for basal CT instead of the previously used 10-ng/l threshold.


The ultrasensitive CT assay reduces the false-negative rate of basal CT measurements when diagnosing familial MTC and in postoperative follow-up compared with previously used assays. However, its sensitivity to detect C-cell disease remains lower than that of the Pg-stimulation test.

[Indexed for MEDLINE]

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