Assay of free thyroxine and free triiodothyronine in fine-needle aspiration of thyroid nodules: a useful and low-cost assessment.
OBJECTIVE
To evaluate whether analysis of thyroid hormones in fine-needle aspiration (FNA) of thyroid nodules can provide information about the functional status and the nature of the nodules.


METHODS
We studied 4 groups of patients: group 1, 17 patients with autonomous hyperfunctioning thyroid nodules; group 2, 52 patients with cold nonfunctioning thyroid nodules; group 3, 12 patients with malignant thyroid nodules; and group 4 (control group), 10 patients with nonthyroid nodular lesions (enlarged parathyroid glands or lymph nodes). The assay of thyroid hormones was performed in FNA after the washing of needles and, with patient consent, also in normal thyroid parenchyma.


RESULTS
The free thyroxine (FT(4)) and free triiodothyronine (FT(3)) values were remarkably high in group 1 (mean, 5.5 +/- 0.53 ng/dL and 27.6 +/- 3.1 pg/mL, respectively; P<0.05 versus group 2 and group 4, the control group). The levels of FT(4) and FT(3) were very low in group 3 (<0.2 ng/dL and <1.0 pg/mL, respectively; P<0.05 versus group 2). Thyroglobulin values in FNA specimens were much higher than the normal range in human serum, but no significant differences were found between the various groups. The control group had low levels of FT(4) and FT(3) (<0.2 ng/dL and <1.0 pg/mL, respectively) in conjunction with low levels of thyroglobulin, whereas parathyroid hormone levels were high in parathyroid nodules.


CONCLUSIONS
These results show that assay of FT(4) and FT(3) in FNA can yield information about the functional status of thyroid nodules and, indirectly, about the nature of nodules. In this era of sophisticated new molecular markers in FNA cytology, this low-cost diagnostic method can be readily performed in every laboratory.
Barbaro
Daniele
D
Sezione Endocrinologia, Diabetologia e Malattie Metaboliche, Spedali Riuniti, Livorno, Italy.
Macchia
Enrico
E
Orsini
Paola
P
Piazza
Francesca
F
Lapi
Paola
P
Pasquini
Cristina
C
D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle / Q000191:economics; D005260:Female; D006801:Humans; D007118:Immunoassay; D008297:Male; D008875:Middle Aged; D016606:Thyroid Nodule / Q000737:chemistry* / Q000473:pathology*; D013974:Thyroxine / Q000032:analysis*; D014284:Triiodothyronine / Q000032:analysis*
D014284:Triiodothyronine; D013974:Thyroxine