Millán J L, Stigbrand T
Clin Chem. 1981 Dec;27(12):2014-8.
Alkaline phosphatase of the placental type in serum has been suggested as a "marker" for malignancy and pregnancy. We describe a highly sensitive enzyme-linked immunosorbent assay (ELISA) for the measurement of this enzyme in serum and ascitic fluid. The assay will detect as little as 0.4 microgram/L, significantly less than with a radioimmunoassay performed with the same reagents. It is highly specific; it does not measure even above-normal concentrations of the intestinal and liver isoenzymes of alkaline phosphatase. The assay is technically simple and allows the processing of many samples in less than 10 h. We measured this isoenzyme in serum of an adult control population. The upper limit of normality is 1.85 microgram/L. Interference by rheumatoid factor was eliminated. Concentrations of the analyte were increased in all pregnancy sera tested. Concentration and activity as measured by two different catalytic assays correlated well. Samples from cancer patients also showed a good correlation, with some exceptions. Possible reasons for these exceptions are discussed. The high sensitivity, specificity, and simplicity of this assay should make it a useful adjunct in monitoring cancer and pregnancy.
血清中胎盘型碱性磷酸酶已被认为是恶性肿瘤和妊娠的一种“标志物”。我们描述了一种用于测定血清和腹水中该酶的高度灵敏的酶联免疫吸附测定法（ELISA）。该测定法能检测低至0.4微克/升的量，明显低于使用相同试剂进行的放射免疫测定法。它具有高度特异性；甚至对高于正常浓度的碱性磷酸酶肠型和肝型同工酶也检测不出。该测定法技术简单，可在不到10小时内处理许多样本。我们在成年对照人群的血清中测量了这种同工酶。正常上限为1.85微克/升。消除了类风湿因子的干扰。在所有检测的妊娠血清中，分析物的浓度均升高。通过两种不同催化测定法测得的浓度和活性相关性良好。癌症患者的样本也显示出良好的相关性，但有一些例外。讨论了这些例外情况的可能原因。该测定法的高灵敏度、特异性和简单性使其应成为监测癌症和妊娠的有用辅助手段。
