OBJECTIVEStudy on the diagnostic accuracy and value of cell block and tissue fragment preparations collected from lung fine needle aspiration (FNA).

METHODSA total of 187 FNA (22G) samples from the lungs with matched histological diagnosis were studied. Among them, the diagnosis made by depending on 124 cell block and fragment preparations were analyzed in comparing retrospectively with the diagnosis of 187 cases by smear preparations.

RESULTS(1) Of the 124 cell blocks cases, 89 cases were true positives, 22 cases were true negatives, 13 cases were false negatives and no false positives. Of the 187 smears cases, the figure were 136, 30, 19 and 2 cases respectively. The diagnostic accuracy of cell blocks was 87.3% in sensitivity, 100% in specificity, 89.5% in overall accuracy. The figures for smears were 87.7%, 93.8% and 88.8% respectively. (2) For malignant tumours, the histological typing accuracy of cell blocks was 93.3% (83/89), and to be 67.9% (91/134) by diagnosis depending on the smears (P < 0.01). For the benign lesions, the figures were 86.4% (19/22) and 60% (18/30) respectively (P < 0.05). (3) It was possible to obtain many minisections for further studies from cell blocks. Immunoperoxidase staining on minisections was reliable and agreed with those on the surgical specimens.

CONCLUSIONSThe diagnostic accuracy of cell block is high, particularly in histological typing which approaches to that of the diagnosis made depending on the postoperative specimens. A combined use of smears and cell block is recommended which may raise further the diagnostic accuracy.