Painter P C, Lyon J M, Evans J H, Powers W W, Whittaker R L, Decker M J
Clin Chem. 1982 Nov;28(11):2214-8.
We evaluated a rate-nephelometric assay for rheumatoid factor (RF), as developed for use with the Beckman Immunochemistry System (ICS). Within- run precision (CV) for low-, mid-, and high-dilution samples (60-400 kilo-int. units/L) was 3.5, 1.5, and 1.6%; between-run precision was 3.4%. Analytical linearity was excellent. Biological interference resulted in some degree of nonlinearity in more than 70% of the patients' samples tested. Sensitivities were 96.5 and 94.1% and specificities were 98.5 and 95.3% for the ICS RF and Wampole slide methods, respectively, for a clinically defined population of 170 patients. Results for 100 ICS RF-positive samples correlated well with concomitantly measured Calbiochem-Behring tube-titers. Weekly measurement of Calbiochem-Behring. Hyland Diagnostics, and ICL Scientific tube-titer values for RF along with the ICS RF values on samples from the same patients indicated stable ICS RF values but showed at least +/- 1 tube dilution variances both within and between the tube-titer methods. Therefore, it may not be appropriate to compare a precise new method with a relatively imprecise comparison method. Treatment of RF-positive samples with dithiothreitol, which disrupts the pentameric character of immunoglobulin M, rendered the samples negative by repeat ICS RF assay and confirmed the method's specificity for pentameric immunoglobulin M-RF. Serum RF concentration as determined by ICS paralleled changes in clinical symptoms in a patient treated with both effective and relatively ineffective regimens, which suggests a useful role for the assay in monitoring efficacy of clinical treatment.
我们评估了一种用于类风湿因子（RF）检测的速率散射比浊法，该方法是为与贝克曼免疫化学系统（ICS）配套使用而开发的。低、中、高稀释度样本（60 - 400千国际单位/升）的批内精密度（CV）分别为3.5%、1.5%和1.6%；批间精密度为3.4%。分析线性良好。在所检测的70%以上患者样本中，生物干扰导致了一定程度的非线性。对于170例临床定义的患者群体，ICS RF法和Wampole玻片法的灵敏度分别为96.5%和94.1%，特异性分别为98.5%和95.3%。100份ICS RF阳性样本的检测结果与同时测定的Calbiochem - Behring试管效价相关性良好。每周对同一患者样本的Calbiochem - Behring、Hyland Diagnostics和ICL Scientific试管效价以及ICS RF值进行测定，结果表明ICS RF值稳定，但在试管效价法内部和之间均显示至少有±1个试管稀释差异。因此，将一种精确的新方法与一种相对不精确的比较方法进行比较可能并不合适。用二硫苏糖醇处理RF阳性样本，二硫苏糖醇会破坏免疫球蛋白M的五聚体特性，经重复ICS RF检测后样本变为阴性，这证实了该方法对五聚体免疫球蛋白M - RF的特异性。在接受有效和相对无效治疗方案的患者中，由ICS测定的血清RF浓度与临床症状变化平行，这表明该检测方法在监测临床治疗疗效方面具有有用的作用。
