The preservation method and timing on accuracy of manual leukocytes counts in synovial fluid

To compare the efficacy of heparin and EDTA and determine the impact of time delays in stabilizing leukocyte counts in synovial fluid.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 measurement.There were good correlations between the leukocyte numbers from the specimens preserved by heparin and EDTA (ICC = 0.889, r = 0.879, P0.0001 at 1 hour and ICC = 0.822, r = 0.693, p0.0001 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, p0. 0001) and were not different from those of the heparinized samples (ICC = 0.833, r = 0. 751, p0.0001) but the ICC value was higher.EDTA was as effective as heparin for preservation of synovial fluid. Therefore, it can be used routinely as a preservative of synovial fluid.