Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0711, USA.
J Acquir Immune Defic Syndr. 2011 Mar 1;56(3):e70-4. doi: 10.1097/QAI.0b013e3181ff63d7.
Similar to other resource-limited settings, cost restricts availability of viral load monitoring for most patients receiving antiretroviral therapy in Tijuana, Mexico. We evaluated if a pooling method could improve efficiency and reduce costs while maintaining accuracy.
We evaluated 700 patient blood plasma specimens at a reference laboratory in Tijuana for detectable viremia, individually and in 10 × 10 matrix pools. Thresholds for virologic failure were set at ≥500, ≥1000 and ≥1500 HIV RNA copies per milliliter. Detectable pools were deconvoluted using pre-set algorithms. Accuracy and efficiency of the pooling method were compared with individual testing. Quality assurance (QA) measures were evaluated after 1 matrix demonstrated low efficiency relative to individual testing.
Twenty-two percent of the cohort had detectable HIV RNA (≥50 copies/mL). Pooling methods saved approximately one third of viral load assays over individual testing, while maintaining negative predictive values of >90% to detect samples with virologic failure (≥50 copies/mL). One matrix with low relative efficiency would have been detected earlier using the developed QA measures, but its exclusion would have only increased relative efficiency from 39% to 42%. These methods would have saved between $13,223 and $14,308 for monitoring this cohort.
Despite limited clinical data, high prevalence of detectable viral loads and a contaminated matrix, pooling greatly improved efficiency of virologic monitoring while maintaining accuracy. By improving cost-effectiveness, these methods could provide sustainability of virologic monitoring in resource-limited settings, and incorporation of developed QA measures will most likely maximize pooling efficiency in future uses.
与其他资源有限的环境类似，成本限制了在墨西哥提华纳为大多数接受抗逆转录病毒治疗的患者提供病毒载量监测。我们评估了一种合并样本的方法是否可以提高效率并降低成本，同时保持准确性。
我们在提华纳的一个参考实验室，单独检测并以 10×10 矩阵池的方式，评估了 700 名患者的血浆标本是否存在可检测的病毒血症。病毒学失败的阈值设定为 HIV RNA 每毫升≥500、≥1000 和≥1500 拷贝。使用预设算法对可检测的池进行反卷积。将合并方法的准确性和效率与个体检测进行比较。在一个矩阵的效率相对个体检测较低时，评估了质量保证（QA）措施。
该队列中有 22%的患者可检测到 HIV RNA（≥50 拷贝/ml）。与个体检测相比，合并方法节省了大约三分之一的病毒载量检测，同时保持了>90%的阴性预测值，以检测病毒学失败（≥50 拷贝/ml）的样本。如果使用开发的 QA 措施，较早地发现一个效率相对较低的矩阵，那么它的排除只会将相对效率从 39%提高到 42%。这些方法将节省 13223 美元至 14308 美元，用于监测这个队列。
尽管临床数据有限、可检测病毒载量的高患病率和受污染的基质，合并样本极大地提高了病毒学监测的效率，同时保持了准确性。通过提高成本效益，这些方法可以为资源有限的环境中的病毒学监测提供可持续性，并且开发的 QA 措施的纳入很可能会在未来的使用中最大限度地提高合并效率。
