本文根据凝血酶原抗体与异常凝血酶原有１００％交叉反应的特点，用凝血酶原免疫家兔获得抗体，建立了血浆异常凝血酶原的放射免疫测定。标准曲线范围为７．８～１００ｎｇ／ｍｌ，最低检测值为７．８ｎｇ／ｍｌ；平均回收率为１００．４％，批内和批间ＣＶ分别为８．３５％和７．７６％。３９名健康人均值为１５４．４９±３３．５２ｎｇ／ｍｌ，１８例原发性肝癌测定值４０６．７８±１５７．４５ｎｇ／ｍｌ．本法简便，对原发性肝癌检测阳性率达７８．０％，高于目前常规ＡＦＰ测定的阳性率。 Based on the characteristic of 100% cross-reaction between prothrombin and prothrombin, the rabbit was immunized with prothrombin to obtain antibody, and the radioimmunoassay of plasma prothrombin was established. The standard curve ranged from 7.8 to 100 ng / ml with the lowest detection value of 7.8 ng / ml. The average recovery was 100.4%. The intra-assay and inter-assay CV were 8.35% and 7.76%, respectively. The mean of 39 healthy individuals was 154.49 ± 33.52ng / ml, and the value of 18 cases of primary liver cancer was 406.78 ± 157.45ng / ml. This method is simple, the positive rate of detection of primary liver cancer up to 78.0%, higher than the current rate of conventional AFP determination.