Fritsche H A, Tashima C K, Collinsworth W L, Geitner A, Van Oort J
J Immunol Methods. 1980;35(1-2):115-28. doi: 10.1016/0022-1759(80)90156-8.
We have incorporated commercially available CEA standard and antiserum into the triple isotope double antibody radioimmunoassay and we have evaluated this assay for the routine determination of CEA. The competitive protein binding (CPB) assay for CEA can be performed directly on serum or plasma without perchloric acid extraction. The assay sensitivity was 0.98 ng/ml, and the day-to-day precision as defined by the coefficient of variation was 12.5% and 13.3% for mean values of 7.6 and 23.9 ng CEA/ml, respectively. The normal range (X +/- 2 S.D.) for CEA determined with the direct CPB method was 3.2--6.2 ng CEA/ml for non-smokers. The upper limit of normal for smokers was 10.0 ng/ml. A method comparison study (Roche perchloric acid extraction vs. direct CPB) showed excellent agreement between the methods for plasma samples containing less than 20.0 ng CEA/ml. The least square analysis parameters were: N = 116, slope = 1.01, y-intercept = 3.5 ng/ml, Sy/x -2.05 ng/ml, and the correlation coefficient was 0.79. Recovery and dilution studies showed no demonstrable non-specific interference due to serum proteins in the direct CPB assay. The clinical significance of the direct CPB assay for CEA was assessed by correlating serial CEA values with the clinical status of patients with breast and colorectal cancer. Increasing CEA values correlated with progressive or recurrent neoplastic disease, and decreasing CEA values correlated with response of the patient to therapy. No false positive direct CPB values for CEA were observed in the clinical study or in the method comparison study. Our laboratory and clinical evaluation demonstrate that the direct CPB method is an accurate and reliable method for the quantitation of CEA. In addition, the method permits high volume analysis and eliminates the hazards to safety that are associated with perchloric acid.
我们已将市售癌胚抗原（CEA）标准品和抗血清纳入三重同位素双抗体放射免疫分析中，并对该分析方法进行了评估，以用于CEA的常规测定。CEA的竞争性蛋白结合（CPB）分析可直接在血清或血浆上进行，无需高氯酸提取。该分析方法的灵敏度为0.98 ng/ml，以变异系数定义的日间精密度对于7.6 ng/ml和23.9 ng/ml的CEA平均值分别为12.5%和13.3%。用直接CPB法测定的非吸烟者CEA正常范围（X±2标准差）为3.2 - 6.2 ng/ml CEA/ml。吸烟者的正常上限为10.0 ng/ml。一项方法比较研究（罗氏高氯酸提取法与直接CPB法）表明，对于CEA含量低于20.0 ng/ml的血浆样本，两种方法之间具有极好的一致性。最小二乘法分析参数为：N = 116，斜率 = 1.01，截距 = 3.5 ng/ml，Sy/x = 2.05 ng/ml，相关系数为0.79。回收率和稀释研究表明，直接CPB分析中血清蛋白未显示出明显的非特异性干扰。通过将连续的CEA值与乳腺癌和结直肠癌患者的临床状况相关联，评估了直接CPB法检测CEA的临床意义。CEA值升高与肿瘤疾病进展或复发相关，而CEA值降低与患者对治疗的反应相关。在临床研究或方法比较研究中未观察到CEA的直接CPB值出现假阳性。我们的实验室和临床评估表明，直接CPB法是一种准确可靠的CEA定量方法。此外，该方法允许进行大量分析，并消除了与高氯酸相关的安全风险。
