Optimal specimen processing of fine needle aspirates of non-Hodgkin lymphoma

Fine needle aspiration (FNA) in conjunction with flow cytometry (FC) is a useful technique for non-Hodgkin's lymphoma (NHL) diagnosis. We sought to investigate the effect of storage medium and time to processing on lymph node (LN) FNA viability. Benign LN FNAs were distributed among Roswell Park Memorial Institute (RPMI), Hanks' Balanced Salt Solution (HBSS) and Dulbecco's Modified Eagle's Medium (DMEM) storage media, and viability was compared at 0, 4.5 and 24 hours. FC survival analysis showed viable cells (%): at 0 hrs: HBSS 83.6%, RPMI 87.7%, DMEM 87.7%. At 4.5 hrs: HBSS 86.3%, RPMI 89.0%, DMEM 78.2%. At 24 hrs: HBSS 82.7%, RPMI 86.7%, DMEM 77.2%. FNA from a peri-pancreatic LN involved by grade 2 follicular lymphoma was stored in RPMI at 4° C and analyzed at 1, 3, 5 and 7 days. Over 90% of follicular lymphoma cells were suitable for FC analysis at 1, 3, and 5 days after collection, decreasing to 76% at 7 days.

RPMI appears to be the optimal storage medium compared to DMEM and HBSS.An NHL FNA sample stored at 4° C remains suitable for FC analysis for up to 5 days.