Value of rapid staining and assessment of ultrasound-guided fine needle aspiration biopsies.

In a series of 160 ultrasonically guided fine needle aspiration (FNA) biopsies, immediate cytologic evaluation of each specimen's adequacy was performed using a rapid staining method. The number of passes was thus limited to what was strictly necessary in order to obtain sufficient material; the average number of passes was only 1.27 per patient. The total series of FNA biopsies had a sensitivity of 95.6%, a specificity of 100% and an overall accuracy of 97.3%. In addition, the cumulative accuracy after each pass was calculated. A significant increase in diagnostic accuracy was found only after the second pass; the third and the fourth passes gave little further improvement. The results indicate that a rapid evaluation of the aspirated material during ultrasound-guided FNA biopsy can reduce the number of punctures needed per case, resulting in less discomfort and, probably, a reduced likelihood of complications for the patient. The results also suggest that a maximum of two punctures will probably yield adequate diagnostic material in most cases.