Objective To investigate the effects of different stabilizers, time and temperature before centrifugation on the stability of homocysteine (Hcy) and other related thiols levels involving EDTA-containing whole blood.Methods Blood was drawn from 17 healthy adults and collected into tubes containing EDTA, EDTA plus NaF and EDTA plus 3-deazaadenosine(3DA),then stored on crush ice(0-4 ℃) immediately or at room temperature(25 ℃).Plasma was separated at 0, 3, 6, 24 and 48 hours, respectively.The levels of plasma total Hcy (tHcy), total cysteine (tCys), tatal cysteinylglycine (tCysGly) and tatal glutathione (tGSH) were measured by HPLC.The plasma immediately separated was used as baseline sample. Results In EDTA tubes stored at room temperature, tHcy levels increased by 38.5%, 64.2%, 141.9%, 225.4% for 3, 6, 24, and 48 h, respectively.The levels of tCysGly and tGSH increased by 20.0% and 37.9% within 3 h, however, tCys decreased by 3.5%.The levels of the thiols increase by less than 5% up to 6 h in EDTA tubes stored on crush ice.In EDTA-3DA and EDTA-NaF tubes, no statistical differences were observed in the plasma levels of tHcy, tCys,tCysGly and tGSH compared with their respective baseline values at room temperature for 3 h(EDTA-3DA tubes:F=0.01,0.94,0.09,0.01,all P>0.05;EDTA-NaF tubes:F=0.85,0.04,0.03,0.02,all P>0.05).Conclusions The EDTA-plasma levels of tHcy and other related thiols are time and temperature-dependent. There is a strong need for standardization of blood sample collection and processing in tHcy and other thiols assays. The plasma concentrations of tHcy, tCys, tCysGly and tGSH were stable for 3 h at least in the EDTA-3DA and EDTA-NaF tubes kept at room temperature.%目的 观察含EDTA的全血样本放置时间、保存温度以及不同稳定剂对血浆同型半胱氨酸(homocysteine,Hcy)及其相关硫醇物水平的影响.方法 用含EDTA、EDTA-氟化钠(EDTA-NaF)、EDTA-3-Deazaadenosine(EDTA-3DA)的试管收集17名健康成人静脉血,置于碎冰上(0～4 ℃)或室温中(25 ℃)保存,放置0、3、6、24、48 h后分离血浆.用HPLC法测定血浆总同型半胱氨酸(tHcy)、总半胱氨酸(total cysteine,tCys)、总半胱氨酰甘氨酸(total cysteinylglycine,tCysGly)、总谷胱甘肽(total glutathione,tGSH)浓度.设定全血样本0 h分离血浆所测硫醇物浓度为基础值.结果 EDTA管在室温中放置3、6、24、48 h,tHcy分别增加38.5%、64.2%、141.9%、225.4%;tCysGly、tGSH在3 h分别增加20.0%、37.9%,tCys则降低3.5%.EDTA管在碎冰上保存,各硫醇物浓度6 h内增加不超过5%.EDTA-3DA和EDTA-NaF管在室温放置3 h,与各自基础值相比,血浆tHcy、tCys、tCysGly、tGSH浓度差异无统计学意义(EDTA-3DA管:F值分别为0.01、0.94、0.09、0.01,P值均>0.05;EDTA-NaF管:F值分别为0.85、0.04、0.03、0.02,P值均>0.05).结论 EDTA抗凝血浆,所测tHcy及其相关硫醇物浓度呈时间、温度依赖性增加.血浆tHcy等硫醇物测定的分析前处理条件必须标准化.EDTA-3DA和EDTA-NaF管可使血浆tHcy、tCys、tCysGly、tGSH在室温中至少稳定3 h.
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