Effects of different sample preservation methods on the lymphocyte subset detection by flow cytometry

Objective To discuss the effects of sample storage time and temperature on lymphocyte subsets detected by flow cytometry. Methods Use flow cytometry to detect lymphocyte subsets of a total of 53 blood samples from hospitalized and out-patient patients in Qinghai Provincial People′s Hospital from October 26, 2018 to March 30, 2019. The test was completed within 4 hours after sample collection, which is the control group. The treatment groups are as follows: pretreatment was completed within 4 hours and detected after saving samples at room temperature (group A) for 24 and 36 hours; the tests were performed after keeping samples at room temperature (group B) for 24, 48, 72 hours; completed detection after preserving samples in 4 ℃ condition (group C) for 24, 48, 72 hours. Results In treatment group A, there was no significant difference in the results of lymphocyte subsets detected after 24 hours of storage compared with the control group(P>0.05); after 36 h of storage, CD3+and CD3+CD8+T lymphocytes percentages were significantly increased [(74.28±11.31)% vs (73.78±11.33)%, (32.15±14.82)% vs (31.00±14.79)%; all P 0.05); after 48 hours of storage, CD19+cells percentage were observably reduced [(15.60±12.09)% vs (16.11±12.38)%; P 0.05); after 72 hours of storage, CD3+and CD3+CD8+T cells percentages elevated significantly [(75.78±11.18)% vs (73.78±11.33)%, (32.57±14.90)% vs (31.00±14.79)%; all P 0.05); after 48 hours of storage, CD3+CD8+T cells percentage elevated obviously [(32.03±14.95)% vs (31.00±14.79)%; P<0.05] and CD19+cells percentage decreased markedly [(15.32±11.97)% vs (16.11±12.38)%; P<0.05]; after 72 hours of storage, CD3+and CD3+CD8+T cells percentages were significantly increased [(75.63±11.08)% vs (73.78±11.33)%, (32.62±14.98)% vs (31.00±14.79)%; all P<0.05], while CD56+and CD19+cells percentages were reduced observably [(8.21±6.52)% vs (9.02±6.80)%, (14.83±11.79)% vs (16.11±12.38)%; all P<0.05]. Conclusions The blood samples can be kept at room temperature and the testshould be completed within 48 h if the detection of lymphocyte subsets by flow cytometry cannot be performed in time; for the samples that have been pretreated, detection can be completed after saving at room temperature for 24 h, and the above treatments had no significant effect on the inspection results. Key words: Lymphocyte subsets; Flow cytometry; Sample preservation