Helfand M, O'Connor G T, Zimmer-Gembeck M, Beck J R
Division of General Internal Medicine, Portland VA Medical Center, OR 97207.
Med Care. 1992 Dec;30(12):1067-82. doi: 10.1097/00005650-199212000-00001.
The Clinical Laboratory Improvement Act of 1988 (CLIA '88) mandates strict, new quality-control measures for laboratories that interpret cervical cytology smears. Proposed regulations include proficiency testing of cytotechnologists and remediation for technologists and laboratories that fail to meet proposed proficiency standards. Proponents of the new regulations argue that these measures will reduce deaths from cervical cancer by reducing the false-negative rate of the Papanicolaou (Pap) test, but opponents argue that the regulations will increase the price of processing Pap tests and thereby reduce access to cervical cancer screening for high-risk, vulnerable populations. To examine these claims the authors used David Eddy's published simulation to model the natural history and detection of cervical neoplasia, and developed a new model to examine the health consequences of diminished access to Pap testing. The authors estimated the false-negative rate of the Pap test and the price elasticity of demand for preventive services on the basis of the published literature, and modeled the entire range of published or quoted predictions about the impact of CLIA '88 on accuracy and price. The results show that, if effects on access are ignored, reducing the false-negative rate from 15% to 5% would prevent 66 invasive cancers per 100,000 average risk women screened. However, under moderate assumptions regarding the effect of price on access, the regulations would prevent only 11 (instead of 66) cancers per 100,000 eligible women. The regulatory effect is very sensitive to the degree of improvement in the false-negative rate and increase in price that the regulations cause. Over the range of assumptions and predictions encountered in the literature and tested in our analysis, the proposed regulations could greatly reduce or greatly increase the incidence of invasive cancer, especially among high-risk and uninsured women. The implementation of the regulations should be delayed until new information regarding the actual false-negative rate of the Pap test allow a more precise estimate of the potential impact on the incidence of cervical cancer.
1988年《临床实验室改进法案》（CLIA '88）要求对解读宫颈细胞学涂片的实验室实施严格的新质量控制措施。拟议的法规包括对细胞技术人员进行能力测试，以及对未达到拟议能力标准的技术人员和实验室进行整改。新法规的支持者认为，这些措施将通过降低巴氏涂片检查的假阴性率来减少宫颈癌死亡人数，但反对者认为，这些法规将提高巴氏涂片检查的处理价格，从而减少高危、弱势群体获得宫颈癌筛查的机会。为了检验这些说法，作者使用大卫·埃迪发表的模拟模型来模拟宫颈肿瘤的自然病史和检测情况，并开发了一个新模型来研究巴氏涂片检查可及性降低对健康的影响。作者根据已发表的文献估计了巴氏涂片检查的假阴性率和预防性服务需求的价格弹性，并对关于CLIA '88对准确性和价格影响的所有已发表或引用的预测进行了建模。结果表明，如果忽略对可及性的影响，将假阴性率从15%降至5%，每10万名接受筛查的平均风险女性中将预防66例浸润性癌。然而，在关于价格对可及性影响的适度假设下，这些法规每10万名符合条件的女性中只能预防11例（而非66例）癌症。监管效果对法规导致的假阴性率改善程度和价格上涨非常敏感。在文献中遇到并在我们的分析中测试的一系列假设和预测范围内，拟议的法规可能会大幅降低或大幅增加浸润性癌的发病率，尤其是在高危和未参保女性中。在获得有关巴氏涂片检查实际假阴性率的新信息，从而能够更精确地估计对宫颈癌发病率的潜在影响之前，应推迟实施这些法规。
