Background: Most guidelines recommend a midstream urine (MSU) or a midstream clean-catch (MSCC) sample for urinalysis. However, whether this sample is better than others is still controversial.
Objectives: To assess the most adequate non-invasive method to collect a urine specimen for diagnosing urinary tract infections (UTI) in symptomatic non-pregnant women.
Methods: This review was conducted according to the Systematic Reviews of Diagnostic Test Accuracy guidelines (PROSPERO CRD42021241758). PubMed was searched paired sample studies and controlled trials. Studies comparing MSCC, MSU without cleaning, first-void urine, and random voiding samples were considered. Studies evaluating invasive methods were excluded. The main outcome was diagnostic accuracy of urine cultures. Contamination rates were evaluated. The risk of bias tool for systematic reviews on diagnostic accuracy (QUADAS-2) was assessed.
Results: Six studies including 1,010 patients were evaluated. Only two studies used paired samples. No study was considered as having low risk of bias. There was no difference in contamination for MSU specimens collected with or without cleansing and between random void urine collection and MSCC. In one study comparing first-void urine with MSU samples, the contamination rate was lower in the latter, but the gold standard of urine culture was only used for one sampling collection.
Conclusions: To the best of our knowledge, this systematic review is the first to assess the evidence available from different exclusively non-invasive urine sampling. Despite being widely recommended, our review did not find consistent evidence that asking women to provide midstream samples with or without cleansing is better.
Keywords: female; systematic review; urinalysis; urinary tract infections; urine specimen collection.
Urine is one type of specimen that can be easily collected from a patient. Urinalysis testing can give the doctor valuable information about the presence of an infection in the urine and the type of microorganism causing this infection. The physician can also use the information from urine testing to diagnose and treat other diseases. The collection of the mid-stream of the urination has always been advocated. However, this recommendation has never been proven with good quality studies, and the results of the studies carried out so far have been controversial. In a systematic review, we recently determined that the use of any specimen during urination is as good as midstream collection when patients are requested to provide a urine sample and in terms of quality even specimens collected without proper cleansing are also comparable to mid-stream collection with cleansing. In the present systematic review, we evaluated the most adequate non-invasive method to collect a urine specimen for diagnosing urinary tract infections in symptomatic non-pregnant women. We identified only six studies comparing different urine sampling techniques and we did not observe any difference regarding the quality of the urine between them.
© The Author(s) 2022. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.