Routine use of ThinPrep method in fine-needle aspiration material as an adjunct to standard smears

The purpose of this study was to evaluate the efficacy of routine use of ThinPrep in fine-needle aspiration (FNA) material as an adjunct to standard smears. We reviewed 50 consecutive, satisfactory-for-evaluation FNA materials in which ThinPrep slides were obtained. In each case, Diff-Quik-stained and Papanicolaou-stained smears were initially prepared, and the ThinPrep slide was made from the needle/syringe rinse. Smears and ThinPrep slides were evaluated for the presence of diagnostic material. In addition, the following questions were addressed: could the final diagnosis be made based on smears only, and did the ThinPrep method add any additional information to the diagnosis? Smears were satisfactory for evaluation in 49/50 cases, and in one case diagnostic material was present on the ThinPrep slide only. Thirty-two out of 50 ThinPrep slides contained material sufficient for evaluation. In 46/50 (92%) cases, final diagnoses could be made based on smears only. In 2 cases, ThinPrep slides showed additional diagnostic material, and in another 2 cases were critical for the diagnosis. The routine use of ThinPrep as an adjunct preparatory method to FNA material is not justified, and is associated with an additional, potentially nonreimbursable cost.