Gieseker Karen E, Roe Martha H, MacKenzie Todd, Todd James K
Department of Epidemiology, University of Colorado Health Sciences Center, Denver, Colorado, USA.
Pediatrics. 2003 Jun;111(6 Pt 1):e666-70. doi: 10.1542/peds.111.6.e666.
The American Academy of Pediatrics recommends that all negative rapid diagnostic tests for Streptococcus pyogenes pharyngitis be backed up by culture, which creates a dilemma for clinicians who must make treatment decisions without complete diagnostic information at the time of visit. The use of a follow-up serial rapid antigen test instead of a follow-up culture would provide a more timely result.
Two swabs were collected from children who were suspected of having S pyogenes pharyngitis. Each swab was used for a culture and an OSOM Ultra Strep A Test rapid antigen test. The gold standard of comparison was defined as the identification of S pyogenes on either of the 2 culture plates. Three diagnostic strategies were evaluated: a single rapid antigen test, a rapid antigen test with follow-up rapid antigen test (rapid-rapid), and a rapid antigen test with follow-up culture (rapid-culture).
A total of 210 (23.7%) of 887 throat cultures with matched data were identified with S pyogenes. A single rapid antigen test had a sensitivity of 87.6% (95% confidence interval [CI]: 83.2%-92.1%), the sensitivity of the rapid-rapid follow-up was 91.4% (95% CI: 87.6%-95.2%), and the sensitivity of the rapid-culture follow-up was 95.7% (95% CI: 93.0%-98.5%), which was significantly higher than the others. As shown in Fig 1, when these test strategies were evaluated on a subgroup with clinical symptoms commonly associated with S pyogenes pharyngitis, the sensitivities all increased and were no longer significantly different. None of the strategies reliably exceeded a 95% sensitivity threshold.
The American Academy of Pediatrics strategy for S pyogenes detection in children with pharyngitis, requiring a backup culture for those with negative antigen tests, was not exceeded by any other test strategy; however, a rapid-rapid diagnostic strategy may approximate it with the use of judicious clinical selection of patients.
美国儿科学会建议，所有针对化脓性链球菌性咽炎的快速诊断检测结果为阴性时，均需进行培养备份，这给临床医生带来了两难境地，因为他们在就诊时必须在没有完整诊断信息的情况下做出治疗决策。使用后续的系列快速抗原检测而非后续培养可以提供更及时的结果。
从疑似患有化脓性链球菌性咽炎的儿童中采集两份咽拭子。每份咽拭子分别用于培养和OSOM Ultra A群链球菌检测快速抗原检测。比较的金标准定义为在两个培养平板中的任何一个上鉴定出化脓性链球菌。评估了三种诊断策略：单次快速抗原检测、快速抗原检测加后续快速抗原检测（快速-快速）以及快速抗原检测加后续培养（快速-培养）。
在887份有匹配数据的咽拭子培养中，共有210份（23.7%）鉴定出化脓性链球菌。单次快速抗原检测的敏感性为87.6%（95%置信区间[CI]：83.2%-92.1%），快速-快速后续检测的敏感性为91.4%（95%CI：87.6%-95.2%），快速-培养后续检测的敏感性为95.7%（95%CI：93.0%-98.5%），显著高于其他检测。如图1所示，当在与化脓性链球菌性咽炎通常相关的临床症状亚组中评估这些检测策略时，敏感性均有所提高且不再有显著差异。没有一种策略能可靠地超过95%的敏感性阈值。
美国儿科学会针对咽炎患儿化脓性链球菌检测的策略，即抗原检测阴性者需进行培养备份，没有被任何其他检测策略超越；然而，快速-快速诊断策略通过明智地临床选择患者可能与之相近。
