The Preservation Method and Timing on Accuracy of Manual Leukocytes Counts in Synovial Fluid
Ajchara Koolvisoot MD*, Umpaiwan Rungbanaphan MD*, Wanrachada Katchamat MD*, Wimol Chinsawangwatanakul MD, PhD**
Affiliation : * Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University ** Department of Clinical Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University
Objectives : To compare the efficacy of heparin and EDTA and determine the impact of time delays in stabilizing
leukocyte counts in synovial fluid.
Materials and Methods : 33 specimens were collected in heparin-preserved and EDTA-preserved containers.
Total cell count was performed manually at 1 hour and 24 hours. Correlation between cell counts from both
preservatives and the leukocyte number at 1 hour and 24 hours were analyzed by means of agreement mea-
surement.
Results : There were good correlations between the leukocyte numbers from the specimens preserved by
heparin and EDTA ( ICC = 0.889, r = 0.879, P < 0.0001 at 1 hour and ICC = 0.822, r = 0.693, p < 0.0001 at
24 hour ). At 24 hours, total cell counts from EDTA-preserved samples were comparable to those obtained at
1 hour ( ICC = 0.985, r = 0.986, p < 0.0001 ) and were not different from those of the heparinized samples ( ICC
= 0.833, r = 0.751, p < 0.0001 ) but the ICC value was higher.
Conclusion : EDTA was as effective as heparin for preservation of synovial fluid. Therefore, it can be used
routinely as a preservative of synovial fluid.
Keywords : Synovial fluid analysis, Leukocyte count, Heparin, EDTA, Preservation
