Objective: To describe and evaluate the value of a simple filtration technique for use in processing haemorrhagic samples for cytomorphological evaluation and immunocytochemistry.
Methods: One hundred and sixty haemorrhagic cytological samples (133 FNAs, 27 effusions) received in our laboratory from August 2002 to September 2005 were included in this study. After preparing two smears for diagnostic evaluation, the residual sample was suspended in 2 ml of a cell medium prepared in our laboratory. These primary haemorrhagic suspensions were filtered through disposable nylon filter devices and the cells deposited on the upper membrane surface were transferred into 2 ml of fresh cell medium. From all three fractions - primary cell suspension, filter deposit and filtrate - cytospins were prepared and stained by Giemsa or Papanicolaou methods. Cytospins were examined under the microscope for the presence of diagnostic cells, red blood cells (RBCs) and debris. Additional cytospins for immunocytochemistry were prepared at the cytopathologist's request.
Results: RBCs and debris were successfully removed in 142 out of 160 haemorrhagic samples (88%) by using this new filtration technique. In all these cases the tumour cells were well presented and allowed substantially improved cytomorphological evaluation. Immunocytochemical staining was performed on 112 filtered samples with three different markers per case on average. Filtration did not improve the quality of cytospins in 18/160 haemorrhagic samples, mostly attributable to insufficient numbers of diagnostic cells in the original samples.
Conclusion: The presented filtration technique is very simple and quick. It substantially improves the quality of haemorrhagic samples for cytomorphological evaluation; moreover, the samples are well suited for multiple immunocytochemical stainings.