Supravital-stained wet film study of fine needle aspirates: A reliable supplementary diagnostic procedure

Background: Fine needle aspiration cytology (FNAC) is a simple, rapid, reliable, and cost-effective method in diagnosing mass lesions. In spite of its advances and advantages, conventional Hematoxyline and Eosin (H and E)-stained wet-fixed smear of FNAC fails to achieve 100% accuracy. To improve the accuracy of cytodiagnosis, toludine blue (TB)-stained wet film preparation of fine needle aspirates is supplemented along with conventional wet-fixed smear. We have assessed the morphology and accuracy of supravital-stained (TB) wet film study of FNAC, which has not been previously reported. Materials and Methods: A total of 197 fine needle aspirates from various body sites were studied both in supravital toludine blue (TB)-stained wet film and hematoxylin and eosin (H and E)-stained wet-fixed smear preparation. The results were interpreted with final diagnosis made by histopathological study, clinical, radiological follow-up and were statistically analyzed. Results: For the entire series, TB-stained wet film study gave a sensitivity of 93.7%, a specificity of 98%, a positive predictive value (PPV) of 96.6%, a negative predictive value (NPV) of 96.9%, and an efficacy of 96.3%. H and E-stained wet smear study revealed a sensitivity of 86.2%, specificity of 97.9%, PPV of 95.4%, NPV of 93.4%, and an efficacy of 93.2%. The combined wet film and wet smear study results showed a sensitivity of 98%, specificity of 99.2%, PPV of 98.4%, NPV of 98.9%, and an efficacy of 98.6%. The decreased sensitivity of wet smear study due to inadequate cellularity, loss of cell sample during fixation and staining, artifactual morphological distortion were minimized by supplementary wet film study and that yielded high accuracy rate. Conclusion: Wet film study gave a good cytomorphological picture and this immediate interpretation was useful for assessing the adequacy of material. False negative and false positive reports were reduced significantly when we combined this toludine blue-stained wet film study and wet smear study. Therefore, it could be regularly undertaken as a supplementary diagnostic procedure for wet smear to improve the diagnostic accuracy.