College of Medicine and Dentistry and Australian Institute of Tropical Health and Medicine, James Cook University, 1 James Cook Drive, Townsville, Qld 4811, Australia
The Children's Hospital at Westmead, Sydney, NSW 2145, Australia
Rural Remote Health. 2021 Feb;21(1):6317. doi: 10.22605/RRH6317. Epub 2021 Feb 10.
Smear-positive pulmonary tuberculosis (PTB) requires rapid diagnosis and treatment to prevent ongoing transmission. Collection of two sputum specimens is considered the minimum requirement for the diagnosis of PTB but current guidelines in the Torres Strait Islands, Australia, recommend three sputum specimens; this frequently delays treatment initiation.
A retrospective study was performed to ascertain the diagnostic yield of sputum specimens collected in the Torres Strait Islands. The study assessed demographics and characteristics of all PTB cases diagnosed between 2000 and 2018, and assessed the diagnostic yield in 143 patients from whom at least three sputum specimens had been collected prior to treatment commencement. Incremental and cumulative yield was calculated for each sputum specimen. Data were further analysed using binary logistic regression to examine the association between selected characteristics and a smear-positive acid-fast bacilli (AFB) result.
Overall, AFB was detected from the first or second sputum specimen in 97 of 101 PTB cases that were sputum smear positive. A smear-positive result was more common (odds ratio 2.84, 95% confidence interval 1.08-7.46) for Papua New Guinea nationals compared to Australian born patients. Of the 429 samples collected, 76 (18%) were of poor quality and the association between poor quality specimens and smear-negative results was significant (p<0.01). Among sputum smear-negative cases, 5/42 (12%) had three consecutive poor quality specimens. The most common collection modality in adults was voluntary expectoration; done in 391/429 (91%) of all specimens collected. Alternative specimen collection methods were mainly used in children; induced sputum 1/429 (0.2%), gastric aspirate 26/429 (6%) and nasopharyngeal aspirate 7/429 (1.6%). Errors with labelling, packaging and transportation occurred in 44 specimens from 15 patients.
Two good quality specimens ensure adequate diagnostic yield for PTB and a third specimen should only be collected from patients with two negative specimens who have persistent symptoms. Ideally, decentralised Xpert Ultra® should be the frontline diagnostic test in remote settings, especially in settings like the Torres Strait Islands with high rates of drug-resistant TB.
涂阳肺结核（PTB）需要快速诊断和治疗，以防止持续传播。采集两份痰标本被认为是诊断 PTB 的最低要求，但澳大利亚托雷斯海峡群岛的现行指南建议采集三份痰标本；这经常会延迟治疗的开始。
本回顾性研究旨在确定托雷斯海峡群岛采集的痰标本的诊断效果。该研究评估了 2000 年至 2018 年间诊断的所有 PTB 病例的人口统计学和特征，并评估了在 143 名至少采集了三份痰标本后开始治疗的患者的诊断效果。计算了每个痰标本的增量和累积产量。进一步使用二项逻辑回归分析数据，以检查所选特征与涂阳抗酸杆菌（AFB）结果之间的关联。
总的来说，在 101 例涂阳的 PTB 病例中，有 97 例在第一或第二份痰标本中检测到 AFB。与澳大利亚出生的患者相比，巴布亚新几内亚国民的涂阳结果更常见（优势比 2.84，95%置信区间 1.08-7.46）。在 429 个样本中，76 个（18%）质量较差，且样本质量差与涂阴结果之间存在显著关联（p<0.01）。在涂阴的病例中，5/42（12%）有连续 3 次质量差的标本。成人中最常见的采集方式是自愿咳痰；在 429 个采集的标本中，391/429（91%）为这种方式。在儿童中主要使用其他的标本采集方法；诱导咳痰 1/429（0.2%），胃抽吸 26/429（6%）和鼻咽抽吸 7/429（1.6%）。在来自 15 名患者的 44 个标本中，出现了标签、包装和运输错误。
两份高质量的标本足以保证对 PTB 的充分诊断效果，对于有持续症状且两份标本均为阴性的患者，仅应采集第三份标本。理想情况下，Xpert Ultra®应该在偏远地区（特别是像托雷斯海峡群岛这样耐药结核率较高的地区）成为一线诊断检测方法。
