Berthelot J M, Maugars Y, Audrain M, Youinou P, Prost A
Rheumatology Unit, Nantes University Hospital, France.
Br J Rheumatol. 1995 Aug;34(8):716-20. doi: 10.1093/rheumatology/34.8.716.
Although antiperinuclear factor (APF) has the same specificity for rheumatoid arthritis (RA) as rheumatoid factor (RF), there is no evidence that this specificity is maintained in patients with positive RF-agglutination tests. Thus, we evaluated the specificity and usefulness of APF for RA diagnosis, regardless of RF titre. APF was tested (1:100 threshold) on 214 sera sent for RF evaluation over a 9-month period. These sera were previously determined to have latex or Rose-Waaler (RW) titres > or = 12 or 4 IU, respectively, but not necessarily above the threshold values of 100 and 32 IU. The APF test was performed blindly, and physicians were not advised of the results. In the patient population (119 RA and 95 non-RA) APF still demonstrated good specificity (0.82) for RA. As expected, APF proved useful for RA diagnosis in 28/33 (85%) RA cases with an RF level below 1:100 for latex and 1:32 for RW, thus reducing the number of 'seronegative' RA from 33/119 to 5/119. However, it also improved the serological positive predictive value for RA, even in cases when RW results were > or = 32 IU. Indeed, the positive predictive value for RA when both tests were positive was 0.94 (68/72), whereas concordant results (either positive or negative) for both APF and RW tests allowed correct classification (RA or non-RA) in 94% of cases.
尽管抗核周因子（APF）对类风湿关节炎（RA）的特异性与类风湿因子（RF）相同，但没有证据表明在RF凝集试验呈阳性的患者中这种特异性得以保持。因此，我们评估了APF对RA诊断的特异性和实用性，而不考虑RF滴度。在9个月的时间里，对214份送检进行RF评估的血清进行了APF检测（阈值为1:100）。这些血清先前已分别确定乳胶或玫瑰-瓦勒（RW）滴度≥12或4 IU，但不一定高于100和32 IU的阈值。APF检测是在不知情的情况下进行的，且未向医生告知检测结果。在患者群体（119例RA患者和95例非RA患者）中，APF对RA仍表现出良好的特异性（0.82）。正如预期的那样，在33例RF水平低于乳胶1:100和RW 1:32的RA病例中，APF被证明对RA诊断有用，从而将“血清阴性”RA的数量从119例中的33例减少到119例中的5例。然而，即使在RW结果≥32 IU的情况下，它也提高了RA的血清学阳性预测值。实际上，当两项检测均为阳性时，RA的阳性预测值为0.94（68/72），而APF和RW检测结果一致（阳性或阴性）时，在94%的病例中可进行正确分类（RA或非RA）。
