Objective: To investigate whether fine needle capillary (FNC) sampling gives quantitatively and qualitatively superior cytologic material as compared to the conventional technique of fine needle aspiration (FNA) when performed by a single aspirator.
Study design: Cross-sectional diagnostic test evaluation study. FNA and FNC were performed by a single operator on 200 diffuse and nodular thyroid lesions.
Results: A statistically significant difference in favor of FNC was observed for the parameter amount of cellular material. For the rest of the parameters--background blood or clot, degree of cellular degeneration, degree of cellular trauma and retention of architecture--the average score favored FNC but was not statistically significant--i.e., smears prepared from FNC displayed cellular material that was more concentrated, less damaged and less likely to be obscured by blood.
Conclusion: Although FNC sampling was diagnostic in a greater number of cases than FNA sampling, this study did not prove a clear superiority of FNC over FNA. Until greater experience shows clear sampling superiority of FNC alone, rather than performing only FNA in diffuse or nodular thyroid lesions, incorporating FNC into the second puncture will definitely improve the quality and quantity of material at the patient's first visit.