Birnie Kate, Hay Alastair D, Wootton Mandy, Howe Robin, MacGowan Alasdair, Whiting Penny, Lawton Michael, Delaney Brendan, Downing Harriet, Dudley Jan, Hollingworth William, Lisles Catherine, Little Paul, O'Brien Kathryn, Pickles Timothy, Rumsby Kate, Thomas-Jones Emma, Van der Voort Judith, Waldron Cherry-Ann, Harman Kim, Hood Kerenza, Butler Christopher C, Sterne Jonathan A C
School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom.
Centre for Academic Primary Care, NIHR School of Primary Care Research, School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom.
PLoS One. 2017 Feb 15;12(2):e0171113. doi: 10.1371/journal.pone.0171113. eCollection 2017.
To compare the validity of diagnosis of urinary tract infection (UTI) through urine culture between samples processed in routine health service laboratories and those processed in a research laboratory.
We conducted a prospective diagnostic cohort study in 4808 acutely ill children aged <5 years attending UK primary health care. UTI, defined as pure/predominant growth ≥105 CFU/mL of a uropathogen (the reference standard), was diagnosed at routine health service laboratories and a central research laboratory by culture of urine samples. We calculated areas under the receiver-operator curve (AUC) for UTI predicted by pre-specified symptoms, signs and dipstick test results (the "index test"), separately according to whether samples were obtained by clean catch or nappy (diaper) pads.
251 (5.2%) and 88 (1.8%) children were classified as UTI positive by health service and research laboratories respectively. Agreement between laboratories was moderate (kappa = 0.36; 95% confidence interval [CI] 0.29, 0.43), and better for clean catch (0.54; 0.45, 0.63) than nappy pad samples (0.20; 0.12, 0.28). In clean catch samples, the AUC was lower for health service laboratories (AUC = 0.75; 95% CI 0.69, 0.80) than the research laboratory (0.86; 0.79, 0.92). Values of AUC were lower in nappy pad samples (0.65 [0.61, 0.70] and 0.79 [0.70, 0.88] for health service and research laboratory positivity, respectively) than clean catch samples.
The agreement of microbiological diagnosis of UTI comparing routine health service laboratories with a research laboratory was moderate for clean catch samples and poor for nappy pad samples and reliability is lower for nappy pad than for clean catch samples. Positive results from the research laboratory appear more likely to reflect real UTIs than those from routine health service laboratories, many of which (particularly from nappy pad samples) could be due to contamination. Health service laboratories should consider adopting procedures used in the research laboratory for paediatric urine samples. Primary care clinicians should try to obtain clean catch samples, even in very young children.
比较在常规卫生服务实验室和研究实验室处理的样本中，通过尿培养诊断尿路感染（UTI）的有效性。
我们对4808名年龄小于5岁、在英国初级卫生保健机构就诊的急性病患儿进行了一项前瞻性诊断队列研究。UTI定义为尿致病菌纯培养/优势菌生长≥105 CFU/mL（参考标准），通过在常规卫生服务实验室和一个中央研究实验室对尿样本进行培养来诊断。我们根据样本是通过清洁中段尿采集还是尿布垫采集，分别计算了由预先指定的症状、体征和试纸检测结果（“指标检测”）预测UTI的受试者工作特征曲线下面积（AUC）。
分别有251名（5.2%）和88名（1.8%）儿童被卫生服务实验室和研究实验室分类为UTI阳性。实验室之间的一致性为中等（kappa = 0.36；95%置信区间[CI] 0.29，0.43），清洁中段尿样本的一致性（kappa = 0.54；95% CI 0.45，0.63）优于尿布垫样本（kappa = 0.20；95% CI 0.12，0.28）。在清洁中段尿样本中，卫生服务实验室的AUC（AUC = 0.75；95% CI 0.69，0.80）低于研究实验室（0.86；95% CI 0.79，0.92）。尿布垫样本的AUC值（卫生服务实验室阳性为0.65 [0.61，0.70]，研究实验室阳性为0.79 [0.70，0.88]）低于清洁中段尿样本。
将常规卫生服务实验室与研究实验室对UTI的微生物学诊断进行比较，清洁中段尿样本的一致性中等，尿布垫样本的一致性较差，且尿布垫样本的可靠性低于清洁中段尿样本。研究实验室的阳性结果似乎比常规卫生服务实验室的阳性结果更有可能反映真正的UTI，常规卫生服务实验室的许多阳性结果（特别是尿布垫样本的结果）可能是由于污染。卫生服务实验室应考虑采用研究实验室用于儿科尿样本的程序。基层医疗临床医生应尽量获取清洁中段尿样本，即使是非常年幼的儿童。
