Boyanton Bobby L, Blick Kenneth E
Department of Pathology, OU Medical Center, University of Oklahoma Health Sciences Center, PO Box 26307 Oklahoma City, OK 73190, USA.
Clin Chem. 2002 Dec;48(12):2242-7.
The stability and stoichiometric changes of analytes in plasma and serum after prolonged contact with blood cells in uncentrifuged Vacutainer tubes were studied.
We simultaneously investigated the stability of 24 analytes (a) after prolonged contact of plasma and serum with blood cells and (b) after immediate separation of plasma and serum (centrifuged twice at 2000g for 5 min). We verified biochemical mechanisms of observed analyte change by concomitant measurement of pH, PCO(2), and PO(2). Hemolysis was qualitatively and semiquantitatively assessed. All specimens were maintained at room temperature (25 degrees C) and analyzed in duplicate 0.5, 4, 8, 16, 24, 32, 40, 48, and 56 h after collection. Statistically significant changes from the 0.5 h mean were determined using repeated-measures ANOVA. The significant change limit was applied to determine clinically significant changes in measured analytes.
Fifteen of 24 analytes in plasma and serum maintained in contact with cells showed clinically relevant changes, with the degree of change more pronounced in most plasma specimens. All analytes in plasma and serum immediately separated from cells after collection were stable.
Storage of uncentrifuged specimens beyond 24 h caused significant changes in most analytes investigated because of (a) glucose depletion and Na(+),K(+)-ATPase pump failure; (b) the movement of water into cells, causing hemoconcentration; and (c) leakage of intracellular constituents and metabolites. Immediate separation of plasma or serum from cells provides optimal analyte stability at room temperature. When prolonged contact of plasma or serum with cells is unavoidable, use of serum is recommended because of the higher instability of plasma analytes.
研究了未离心的真空采血管中血浆和血清中的分析物在与血细胞长时间接触后的稳定性和化学计量变化。
我们同时研究了24种分析物的稳定性，（a）血浆和血清与血细胞长时间接触后，以及（b）血浆和血清立即分离后（以2000g离心两次，每次5分钟）。通过同时测量pH、PCO₂和PO₂来验证观察到的分析物变化的生化机制。对溶血进行了定性和半定量评估。所有标本均保存在室温（25℃）下，并在采集后0.5、4、8、16、24、32、40、48和56小时进行双份分析。使用重复测量方差分析确定与0.5小时平均值相比有统计学意义的变化。应用显著变化限值来确定所测分析物的临床显著变化。
与细胞接触保存的血浆和血清中的24种分析物中有15种显示出临床相关变化，大多数血浆标本中的变化程度更为明显。采集后立即与细胞分离的血浆和血清中的所有分析物均稳定。
未离心标本保存超过24小时会导致所研究的大多数分析物发生显著变化，原因如下：（a）葡萄糖消耗和钠钾ATP酶泵功能衰竭；（b）水进入细胞，导致血液浓缩；（c）细胞内成分和代谢产物泄漏。血浆或血清与细胞立即分离可在室温下提供最佳的分析物稳定性。当血浆或血清与细胞不可避免地长时间接触时，由于血浆分析物的不稳定性较高，建议使用血清。
