Department of Medical Biochemistry at Radiumhospitalet, Oslo University Hospital, Oslo, Norway.
J Immunol Methods. 2010 Feb 28;353(1-2):145-7. doi: 10.1016/j.jim.2009.12.001. Epub 2009 Dec 17.
Calibrator matrix can have significant effects on the commutability of assay standards and on the maintenance of their integrity. We have observed marked instability in progastrin-releasing peptide (proGRP) assay standards traceable to the bovine serum albumin (BSA) used in matrix formulation. Attempts were made to improve calibrator stability using different albumin pretreatments. Observed analyte recoveries in calibrators prepared with untreated BSA were consistently less than 45% after 1 week of storage at 4 degrees C. Pre-treating the BSA by chromatography on immobilized heparin or benzamidine failed to improve calibrator durability with day 7 recoveries of less than 55%. In marked contrast, calibrators formulated with albumin pasteurized at pH 3.0 displayed remarkable stability. Recoveries of >97% were observed after 4 weeks of storage at either 4 degrees C or room temperature. Even calibrators incubated for 4 weeks at 37 degrees C gave recoveries between 91-106%. This improvement was not seen with BSA pasteurized at neutral pH. Albumin pretreatment is straightforward, easily scalable and dramatically improves calibrator stability. Matrix formulated with acid-pasteurized BSA may prove more generally useful when assays are plagued by poor calibrator durability.
校准品矩阵对检测物标准品的互换性和完整性保持具有显著影响。我们发现，与基质配方中使用的牛血清白蛋白（BSA）相关的胃泌素释放肽（proGRP）检测物标准品明显不稳定。尝试使用不同的白蛋白预处理方法来提高校准品稳定性。在用未处理的 BSA 制备的校准品中，在 4°C 下储存 1 周后，观察到的分析物回收率始终低于 45%。通过固定化肝素或苯甲脒的色谱法预处理 BSA，未能改善校准品的耐用性，第 7 天的回收率低于 55%。相比之下，在 pH 值为 3.0 巴氏消毒的白蛋白中配制的校准品显示出显著的稳定性。在 4°C 或室温下储存 4 周后，回收率>97%。即使在 37°C 孵育 4 周的校准品，回收率也在 91-106%之间。中性 pH 值巴氏消毒的 BSA 没有观察到这种改善。白蛋白预处理简单、易于扩展，可显著提高校准品稳定性。用酸巴氏消毒的 BSA 配制的基质可能在检测物校准品耐用性差时更具普遍适用性。
