Van Hoof V O, Martin M, Blockx P, Prove A, Van Oosterom A, Couttenye M M, De Broe M E, Lepoutre L G
Department of Clinical Chemistry, University Hospital Antwerp, Edegem, Belgium.
Clin Chem. 1995 Jun;41(6 Pt 1):853-7.
Agarose electrophoresis (Isopal, Beckman) and an immunoradiometric assay (IRMA) involving specific monoclonal antibodies (Ostase, Hybritech), two methods for the quantification of serum bone alkaline phosphatase (ALP, EC 3.1.3.1), a marker of osteoblastic activity, were compared in 293 patients: 79 with end-stage renal failure treated with hemodialysis and 214 with malignant disease. Overall correlation between the two methods was good (r = 0.92), except (a) for low values of bone ALP and (b) in some samples with high total liver ALP activity--both due to considerable cross-reactivity of the anti-bone ALP antibodies of the Ostase kit with liver ALP. This interference was not constant and was not evenly distributed across all concentrations of bone ALP. Low bone ALP determined with the IRMA (< or = 5 micrograms/L) was confirmed by electrophoresis (< or = 21 U/L), but bone ALP activity determined by electrophoresis to be low (< or = 21 U/L) was not correlated with the IRMA results. After standardizing our results by computing z-values for bone ALP, delta z (= zOstase - zIsopal) was significantly correlated with liver ALP activity (r = 0.73, P < 0.0001). We conclude that the IRMA for quantifying bone ALP is acceptable as a screening method. However, when high values for bone ALP are found with the Ostase method, confirmation by electrophoresis remains mandatory to rule out cross-reactivity with high amounts of liver ALP. For detecting low bone ALP activities, electrophoresis remains the method of choice.
对293例患者比较了两种定量血清骨碱性磷酸酶（一种成骨细胞活性标志物，ALP，EC 3.1.3.1）的方法：琼脂糖电泳（Isopal，贝克曼公司）和使用特异性单克隆抗体的免疫放射分析（IRMA，Ostase，Hybritech公司）。这293例患者包括79例接受血液透析治疗的终末期肾衰竭患者和214例恶性疾病患者。两种方法总体相关性良好（r = 0.92），但存在以下两种情况除外：（a）骨ALP值较低时；（b）一些总肝ALP活性较高的样本中，这两种情况均归因于Ostase试剂盒中抗骨ALP抗体与肝ALP有相当程度的交叉反应。这种干扰并不恒定，且在骨ALP的所有浓度中分布不均。用IRMA测定的低骨ALP（≤5微克/升）经电泳证实（≤21 U/L），但电泳测定的低骨ALP活性（≤21 U/L）与IRMA结果不相关。通过计算骨ALP的z值对结果进行标准化后，δz（= zOstase - zIsopal）与肝ALP活性显著相关（r = 0.73，P < 0.0001）。我们得出结论，用于定量骨ALP的IRMA作为一种筛查方法是可以接受的。然而，当用Ostase方法发现骨ALP值较高时，仍必须通过电泳进行确认，以排除与大量肝ALP的交叉反应。对于检测低骨ALP活性，电泳仍是首选方法。
