Reducing non-diagnostic Thyroid FNA rates using 2 pass technique
Russell Young, Cirencester Radiology Department, Gloucestershire Hospitals NHS Foundation Trust, Gloucester.
Thyroid Fine Needle Aspiration (FNA) is a low risk technique with non-diagnostic cytology reported in up to 40% of patients in the literature, although the number of needle passes is not usually specified. A study from Brazil in 2012 has suggested that a two-pass needle technique is optimal.
An audit of a total of 112 Thyroid FNAs was performed by the author between July 2010 and May 2017; 64 used a one-pass technique, and 48 used a two-pass technique. The percentage of non-diagnostic FNAs (Thy1) was 31% with the one-pass technique, reducing to 15% with a two-pass technique. Non-diagnostic FNAs likely to be cysts (Thy1c) were found in 45% using the one-pass technique, reducing to 31% with the two-pass technique.
In summary, the two-pass needle technique shows a clear reduction in the rate of non-diagnostic FNAs, therefore the author will continue to use this technique.