Suligoi Barbara, Galli Claudio, Massi Mario, Di Sora Fiorella, Sciandra Mauro, Pezzotti Patrizio, Recchia Olga, Montella Francesco, Sinicco Alessandro, Rezza Giovanni
Reparto AIDS e MST, Istituto Superiore di Sanità, Ospedale S. Giovanni-Addolorata, Rome, Italy.
J Clin Microbiol. 2002 Nov;40(11):4015-20. doi: 10.1128/JCM.40.11.4015-4020.2002.
We evaluated the precision and accuracy of a procedure for detecting recent human immunodeficiency virus (HIV) infections, specifically, the avidity index (AI) calculated using a method based on an automated AxSYM HIV 1/2gO assay (Abbott). To evaluate precision, we performed multiple replicates on eight HIV-positive serum samples. To evaluate the accuracy in identifying recent infections (i.e., within 6 months of seroconversion), we used 216 serum samples from 47 persons whose dates of seroconversion were known. To evaluate the sensitivity and specificity of the procedure for different AI cutoff values, we performed receiver operating characteristic (ROC) analysis. To determine the effects of antiretroviral treatment, advanced stage of the disease (i.e., low CD4-cell count), and low HIV viral load on the AI, we analyzed 15 serum samples from 15 persons whose dates of seroconversion were unknown. The precision study showed that the procedure was robust (i.e., the total variance of the AI was lower than 10%). Regarding accuracy, the mean AI was significantly lower for samples collected within 6 months of seroconversion, compared to those collected afterwards (0.68 +/- 0.16 versus 0.99 +/- 0.10; P < 0.0001), with no overlap of the 95% confidence intervals. The ROC analysis revealed that an AI lower than 0.6 had a sensitivity of 33.3% and a specificity of 98.4%, compared to 87.9 and 86.3%, respectively, for an AI lower than 0.9. Antiretroviral treatment, low CD4-cell count, and low viral load had no apparent effect on the AI. In conclusion, this procedure is reproducible and accurate in identifying recent infections; it is automated, inexpensive, and easy to perform, and it provides a quantitative result with different levels of sensitivity and specificity depending on the selected cutoff.
我们评估了一种检测近期人类免疫缺陷病毒（HIV）感染方法的精密度和准确性，具体而言，评估了使用基于自动化AxSYM HIV 1/2 gO检测法（雅培公司）计算的亲和力指数（AI）。为评估精密度，我们对8份HIV阳性血清样本进行了多次重复检测。为评估识别近期感染（即血清转换后6个月内）的准确性，我们使用了来自47名已知血清转换日期者的216份血清样本。为评估该方法针对不同AI临界值的敏感性和特异性，我们进行了受试者操作特征（ROC）分析。为确定抗逆转录病毒治疗、疾病晚期（即低CD4细胞计数）和低HIV病毒载量对AI的影响，我们分析了来自15名血清转换日期未知者的15份血清样本。精密度研究表明该方法具有稳健性（即AI的总方差低于10%）。关于准确性，血清转换后6个月内采集的样本的平均AI显著低于之后采集的样本（0.68±0.16对0.99±0.10；P<0.0001），95%置信区间无重叠。ROC分析显示，AI低于0.6时敏感性为33.3%，特异性为98.4%，而AI低于0.9时敏感性和特异性分别为87.9%和86.3%。抗逆转录病毒治疗、低CD4细胞计数和低病毒载量对AI无明显影响。总之，该方法在识别近期感染方面具有可重复性和准确性；它是自动化的，成本低廉且易于操作，并且根据所选临界值可提供具有不同敏感性和特异性水平的定量结果。
