Home-voided urine specimens in women. Diagnostic agreement with clean-catch midstream specimens

Best methods for urine sample collection for diagnostic accuracy in women with urinary tract infection symptoms: a systematic review

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.

The prevalence of positive urine dipstick testing and urine culture in the asymptomatic pregnant woman: A cross-sectional study

OBJECTIVE

Pregnancy induces unique physiological changes to the urinary tract, leaving pregnant women more susceptible to pyelonephritis. Urinary tract infections are generally diagnosed using urine sampling and testing with reagent sticks (dipstick) or laboratory culture. This study aimed to establish the prevalence of positive urine reagent strip and urine culture in asymptomatic pregnant women.

STUDY DESIGN

This was a cross-sectional study of 300 women attending routine antenatal clinics. Samples were analysed using an automated urine dipstick analyser for the presence of glucose, protein, leucocyte esterase, blood, and nitrites. All samples were cultured. Multinomial logistic regression was performed to investigate risk factors for urine contamination and infection. Sensitivities and specificities were calculated for common dipstick findings for positive and mixed urine culture.

RESULTS

One-in-three (37.0 % [111/300], 95 % CI 31.6-42.8 %) women had at least one positive finding on reagent strip testing. Ten per cent ([29/300], 95 % CI 6.7-13.7 %) of samples had a positive culture for a single organism, whereas 46.7 % ([140/300], 95 % CI 40.9-52.5 %) of samples were positive for multiple organisms (mixed culture). 43.7 % ([131/300], 95 % CI 38.0-49.5 %) of samples had a negative culture. Organisms cultured were similar to previous reports from high-income countries. BMI was identified on regression analysis as a risk factor for contamination.

CONCLUSIONS

There is a high prevalence of positive urine dipstick and contaminated culture in asymptomatic pregnant women. BMI is a risk factor for urine culture contamination and further research into this topic is essential given trends in obesity worldwide.

Urine sampling techniques in symptomatic primary-care patients: a diagnostic accuracy review

Background

Choice of urine sampling technique in urinary tract infection may impact diagnostic accuracy and thus lead to possible over- or undertreatment. Currently no evidencebased consensus exists regarding correct sampling technique of urine from women with symptoms of urinary tract infection in primary care. The aim of this study was to determine the accuracy of urine culture from different sampling-techniques in symptomatic non-pregnant women in primary care.

Methods

A systematic review was conducted by searching Medline and Embase for clinical studies conducted in primary care using a randomized or paired design to compare the result of urine culture obtained with two or more collection techniques in adult, female, non-pregnant patients with symptoms of urinary tract infection. We evaluated quality of the studies and compared accuracy based on dichotomized outcomes.

Results

We included seven studies investigating urine sampling technique in 1062 symptomatic patients in primary care. Mid-stream-clean-catch had a positive predictive value of 0.79 to 0.95 and a negative predictive value close to 1 compared to sterile techniques. Two randomized controlled trials found no difference in infection rate between mid-stream-clean-catch, mid-stream-urine and random samples.

Conclusions

At present, no evidence suggests that sampling technique affects the accuracy of the microbiological diagnosis in non-pregnant women with symptoms of urinary tract infection in primary care. However, the evidence presented is in-direct and the difference between mid-stream-clean-catch, mid-stream-urine and random samples remains to be investigated in a paired design to verify the present findings.

Electronic supplementary material

The online version of this article (doi:10.1186/s12875-016-0465-4) contains supplementary material, which is available to authorized users.

Holm S, Ferry BM, Monsen TJ. High Diagnostic Accuracy of Nitrite Test Paired with Urine Sediment can Reduce Unnecessary Antibiotic Therapy

BACKGROUND

Urinary tract infections (UTIs) are common bacterial infections dominated by lower UTI in women (LUTIW). Symptoms only are insufficient for diagnosis and accordingly, near patient diagnostic tests confidently confirming significant bacteriuria are desirable. The nitrite test (NIT) has low sensitivity, while bacterial and leukocyte counts disjunctively paired in urine sediment microscopy (SED) have high sensitivity. Similar symptomatic cure rates are found post antibiotic vs. placebo therapy in patients with negative cultures. Consequently, prescription on symptoms only implies unnecessary antibiotic therapy.

AIMS

to evaluate the diagnostic outcomes of NIT, SED and NIT disjunctively paired with SED (NIT+SED) vs. urine culture, with special focus on bladder incubation time (BIT), and to assess if NIT+SED can reduce unnecessary antibiotic therapy.

METHODS

A diagnostic, primary care, multicentre study including 1070 women with symptoms suggestive of lower UTI.

RESULTS

Significant bacteriuria was found in 77%. The BIT highly influenced the diagnostic outcomes and the optimal duration was ≥4h with sensitivity of 66, 90 and 95% for NIT, SED and NIT+SED, respectively. SED performed only in NIT negative specimens could reduce unnecessary antibiotics by 10% vs. prescription on symptoms only. The number needed to test with SED to reduce one unnecessary antibiotic course was five patients at BIT ≥4h and six patients at ≤3h or overall.

CONCLUSION

The BIT highly influences the diagnostic outcomes with the highest accuracy of NIT+SED. Diagnosis of LUTIW with NIT+SED can reduce unnecessary antibiotic therapy and subsequently decrease antimicrobial resistance.

TRIAL REGISTRATION

The Swedish Medical Product Agency 1995 03 01:151:01783/94.

Toward a simple diagnostic index for acute uncomplicated urinary tract infections

PURPOSE

Whereas a diagnosis of acute uncomplicated urinary tract infection (UTI) in clinical practice comprises a battery of several diagnostic tests, these tests are often studied separately (in isolation from other test results). We wanted to determine the value of history and urine tests for diagnosis of uncomplicated UTIs, taking into account their mutual dependencies and information from preceding tests.

METHODS

Women with painful and/or frequent micturition answered questions about their signs and symptoms (history) of UTIs and underwent urine tests. A culture was the reference standard (10(3) colony-forming units per milliliter). A diagnostic index was derived using logistic regression with bootstrapped backward selection and parameter-wise shrinkage. Risk thresholds for UTI of 30% and 70% were used to analyze discriminative properties. Six models were compared: (1) history only, (2) history+ urine dipstick, (3) history+ urine dipstick + urinary sediment, (4) history+ urine dipstick+ dipslide, and (5) history+ urine dipstick+ urinary sediment+ dipslide; we then added (6) a test only for patients with an intermediate risk (between 30% and 70%) after the preceding test.

RESULTS

One hundred ninety-six women were included (UTI prevalence 61%). Seven variables were selected from history (3), dipstick (2), sediment (1), and dipslide (1). History correctly classified 56% of patients as having a UTI risk of either <30% or >70%. History and urine dipstick raised this to 73%. The 3 models with the addition of urinary sediment and dipslide, separately and in combination, performed hardly better. The sixth model, in which those at intermediate risk after history and received an additional test, correctly classified 83%. The patient's suspicion of a UTI and a positive nitrite test were the strongest indicators of a UTI.

CONCLUSIONS

Most women with painful and/or frequent micturition can be correctly classified as having either a low or a high risk of UTI by asking 3 questions: Does the patient think she has a UTI? Is there at least considerable pain on micturition? Is there vaginal irritation? Other women require additional urine dipstick investigation. Sediment and dipslide have little added value. External validation of these recommendations is required before they are implemented in practice.

Women with symptoms of uncomplicated urinary tract infection are often willing to delay antibiotic treatment: a prospective cohort study

BACKGROUND

Women presenting with symptoms of acute uncomplicated urinary tract infection (UTI) are often prescribed antibiotics. However, in 25 to 50% of symptomatic women not taking antibiotics, symptoms recover spontaneously within one week. It is not known how many women are prepared to delay antibiotic treatment. We investigated how many women presenting with UTI symptoms were willing to delay antibiotic treatment when asked by their general practitioner (GP).

METHODS

From 18 April 2006 until 8 October 2008, in a prospective cohort study, patients were recruited in 20 GP practices in and around Amsterdam, the Netherlands. Healthy, non-pregnant women who contacted their GP with painful and/or frequent micturition for no longer than seven days registered their symptoms and collected urine for urinalysis and culture. GPs were requested to ask all patients if they were willing to delay antibiotic treatment, without knowing the result of the culture at that moment. After seven days, patients reported whether their symptoms had improved and whether they had used any antibiotics.

RESULTS

Of 176 women, 137 were asked by their GP to delay antibiotic treatment, of whom 37% (51/137) were willing to delay. After one week, 55% (28/51) of delaying women had not used antibiotics, of whom 71% (20/28) reported clinical improvement or cure. None of the participating women developed pyelonephritis.

CONCLUSIONS

More than a third of women with UTI symptoms are willing to delay antibiotic treatment when asked by their GP. The majority of delaying women report spontaneous symptom improvement after one week.

The diagnosis of urinary tract infection: a systematic review

BACKGROUND

Urinary tract infections (UTI) are among the leading reasons for treatment in adult primary care medicine, accounting for a considerable percentage of antibiotic prescriptions. Because this problem is so common and so significant in routine clinical practice, a high level of diagnostic accuracy is essential. Antibiotics should not be prescribed excessively, particularly in view of the increasing prevalence of antibiotic resistance.

METHOD

Systematic review of relevant articles that were retrieved by a search of the Medline, Embase, and Cochrane Library databases. The recommendations of selected international guidelines were also taken into account, as were the German national quality standards for microbiological diagnosis.

RESULTS

The diagnosis of UTI by clinical criteria alone has an error rate of approximately 33%. The use of refined diagnostic algorithms does not completely eliminate uncertainty.

CONCLUSION

With the aid of a small number of additional diagnostic criteria, antibiotic treatment for UTI can be provided more specifically and thus more effectively. Differentiating UTI from asymptomatic bacteriuria, which usually requires no treatment, can lower the frequency of unnecessary antibiotic prescriptions.

Optimizing the diagnostic work-up of acute uncomplicated urinary tract infections

BACKGROUND

Most diagnostic tests for acute uncomplicated urinary tract infections (UTIs) have been previously studied in so-called single-test evaluations. In practice, however, clinicians use more than one test in the diagnostic work-up. Since test results carry overlapping information, results from single-test studies may be confounded. The primary objective of the Amsterdam Cystitis/Urinary Tract Infection Study (ACUTIS) is to determine the (additional) diagnostic value of relevant tests from patient history and laboratory investigations, taking into account their mutual dependencies. Consequently, after suitable validation, an easy to use, multivariable diagnostic rule (clinical index) will be derived.

METHODS

Women who contact their GP with painful and/or frequent micturition undergo a series of possibly relevant tests, consisting of patient history questions and laboratory investigations. Using urine culture as the reference standard, two multivariable models (diagnostic indices) will be generated: a model which assumes that patients attend the GP surgery and a model based on telephone contact only. Models will be made more robust using the bootstrap. Discrimination will be visualized in high resolution histograms of the posterior UTI probabilities and summarized as 5th, 10th, 25th 50th, 75th, 90th, and 95th centiles of these, Brier score and the area under the receiver operating characteristics curve (ROC) with 95% confidence intervals. Using the regression coefficients of the independent diagnostic indicators, a diagnostic rule will be derived, consisting of an efficient set of tests and their diagnostic values. The course of the presenting complaints is studied using 7-day patient diaries. To learn more about the natural history of UTIs, patients will be offered the opportunity to postpone the use of antibiotics.

DISCUSSION

We expect that our diagnostic rule will allow efficient diagnosis of UTIs, necessitating the collection of diagnostic indicators with proven added value. GPs may use the rule (preferably after suitable validation) to estimate UTI probabilities for women with different combinations of test results. Finally, in a subcohort, an attempt is made to identify which indicators (including antibiotic treatment) are useful to prognosticate recovery from painful and/or frequent micturition.

[Symptomatic urinary tract infection of the female--diagnostics]

The basis for the diagnostic work-up of recurrent cystitis is formed by taking a precise medical history against the background of knowledge of the pathogenesis of urinary tract infections. The anamnesis should also focus on factors that influence the natural flora (sexual intercourse, hygiene) but additionally include preceding antibiotic treatment and diseases that affect the immune status (diabetes mellitus). Urinalysis is the principal examination among the laboratory diagnostic procedures. The diagnosis is promptly confirmed by immediate analysis of a clean catch midstream urine sample using a counting chamber or a test strip. As a matter of principle, microbiological diagnosis always ensues. Extended diagnostic work-up (urological staging) is aimed at detecting functional and anatomic abnormalities. While these factors only play a subordinate role during the premenopausal phase, they gain in importance during the postmenopausal phase. A key role is also attributed to local estrogen deficiency.

A novel midstream urine-collection device reduces contamination rates in urine cultures amongst women

OBJECTIVE

To evaluate a novel urine-collection device (UCD) that automatically collects a midstream urine (MSU) sample, and compare contamination rates to those of the conventional MSU sampling method, as the contamination of urine samples for microbiological analysis in women leads to diagnostic ambiguity and unnecessary costs, and may result in part from an incorrect collection procedure.

PATIENTS AND METHODS

In all, 2823 women from four centres, most from antenatal clinics, were randomized to two urine-collection methods: conventional MSU collection and collection with a novel MSU UCD (the Whiz, JBOL Ltd, Oxford, UK). Semi-quantitative growth and user acceptability were compared between the collection methods.

RESULTS

MSU samples collected with the UCD had significantly fewer mixed growth samples (9% vs 14%, P = 0.001; 36% relative reduction), significantly fewer heavy mixed growth samples (1.2% vs 3.0%, P = 0.004; 60% relative reduction) and required significantly fewer re-tests (11% vs 16%, P = 0.002; 31% relative reduction). There were more samples with clinically insignificant growth than the conventional MSU group (86% vs 82%, P = 0.005). Those using the UCD preferred it to the conventional method (67.5%) and experienced significantly less spillage during sample collection (27% vs 46%, P = 0.001; relative reduction 41%).

CONCLUSION

The UCD reduced contamination rates in urine samples and improved the predictive value of the urine culture in a manner acceptable to patients and staff.