Recommendations
Urgent
Think ‘Could this be sepsis?’ based on acute deterioration in a patient in whom there is clinical evidence or strong suspicion of infection.[37][38][39] See Sepsis in adults.
Use a systematic approach (e.g., National Early Warning Score 2 [NEWS2]), alongside your clinical judgement for assessment; urgently consult a senior clinical decision-maker (e.g., ST4 level doctor in the UK) if you suspect sepsis.[37][39][40][41]
Refer to local guidelines for the recommended approach at your institution for assessment and management of the patient with suspected sepsis.
Send urine for culture before giving antibiotics if there are signs or symptoms of sepsis in a patient with suspected UTI.[4]
In the community: refer for emergency medical care in hospital (usually by blue-light ambulance in the UK) any patient who is acutely ill with a suspected infection and is:[39]
Deemed to be at high risk of deterioration due to organ dysfunction (as measured by risk stratification)
At risk of neutropenic sepsis.
Check for the following new signs and symptoms of pyelonephritis in all patients, as this can result from ascending infection and is a common complication of lower UTI:[4]
Kidney pain/tenderness in the back, under the ribs
New or different myalgia, or flu-like symptoms
Nausea or vomiting
Rigors
Temperature over 37.9°C (or ≤36°C in women over 65 years).
Send urine for culture (before giving antibiotics) if signs or symptoms of pyelonephritis are present.[4]
Consider the risk of preterm delivery in pregnant women as this is associated with UTI in pregnancy.[42]
Call the on-call obstetric team for advice if there are any signs of preterm labour such as abdominal pain, vaginal bleeding, or premature rupture of the membranes.
Consider onward referral for suspected bladder cancer. Refer the following patients using a suspected cancer pathway referral (for an appointment within 2 weeks):[43]
Aged 45 years and over with:
Unexplained visible haematuria without UTI, or
Visible haematuria that persists or recurs after successful treatment of UTI.
Aged 60 years and over with unexplained non-visible haematuria and either dysuria or a raised white cell count on a blood test.
Consider a non-urgent referral for bladder cancer in people aged 60 years and over with recurrent or persistent unexplained UTI.[43]
Key Recommendations
Be aware of the key symptoms of a UTI in women under 65 years: dysuria, new nocturia, and cloudy-looking urine.[4]
Be aware of the key symptoms of a UTI in women over 65 years: new onset dysuria or 2 or more of:[4]
Temperature 1.5°C above normal for the patient twice in last 12 hours
New frequency or urgency
New incontinence
New or worsening delirium
New suprapubic pain
New haematuria.
Order investigations according to the woman’s age and whether a catheter is in situ.
The main investigations include visual assessment of the urine, urine dipstick, and urine sample for culture.
Sepsis
Think ‘ Could this be sepsis?’ based on acute deterioration in a patient in whom there is clinical evidence or strong suspicion of infection.[37][38][39] See Sepsis in adults.
The patient may present with non-specific or non-localised symptoms (e.g., acutely unwell with a normal temperature) or there may be severe signs with evidence of multi-organ dysfunction and shock.[37][38][39]
Remember that sepsis represents the severe, life-threatening end of infection.[44]
Urosepsis can result from ascending infection.
The urinary tract is the fourth most common site of infection in people with sepsis.[45] The genitourinary tract is the most common site of infection in people aged over 65 years with sepsis.[46]
Use a systematic approach (e.g., National Early Warning Score 2 [NEWS2]), alongside your clinical judgement to assess the risk of deterioration due to sepsis.[37][38][40][47] Consult local guidelines for the recommended approach at your institution.
Arrange urgent review by a senior clinical decision-maker (e.g., ST4 level doctor in the UK) if you suspect sepsis:[41]
Within 30 minutes for a patient who is critically ill (e.g., NEWS2 score of 7 or more, evidence of septic shock, or other significant clinical concerns)
Within 1 hour for a patient who is severely ill (e.g., NEWS2 score of 5 or 6).
Follow your local protocol for investigation and treatment of all patients with suspected sepsis, or those at risk. Start treatment promptly. Determine urgency of treatment according to likelihood of infection and severity of illness, or according to your local protocol.[41]
Send urine for culture (before giving antibiotics) if signs or symptoms of sepsis or pyelonephritis are present.[4]
In the community, refer for emergency medical care in hospital (usually by blue-light ambulance in the UK) any patient who is acutely ill with a suspected infection and is:[39]
Deemed to be at high risk of deterioration due to organ dysfunction (as measured by risk stratification)
At risk of neutropenic sepsis.
Pyelonephritis
Check for the following new signs and symptoms of pyelonephritis in all patients, as this can result from ascending infection and is a common complication of lower UTI:[4]
Kidney pain/tenderness in the back, under the ribs
New or different myalgia, or flu-like symptoms
Nausea or vomiting
Rigors
Temperature over 37.9°C (or ≤36°C in women over 65 years).
Rule out other localised infections in patients over 65 years with no kidney pain.
Send urine for culture (before giving antibiotics) if signs or symptoms of sepsis or pyelonephritis are present.[4]
See Acute pyelonephritis.
Practical tip
Public Health England gives different recommendations for diagnosing UTI in women aged under 65 and over 65 years.[4] This is based on:
Bladder cancer
Consider onward referral for suspected bladder cancer. Refer the following patients using a suspected cancer pathway referral (for an appointment within 2 weeks):[43]
Aged 45 years and over with:
Unexplained visible haematuria without UTI, or
Visible haematuria that persists or recurs after successful treatment of UTI.
Aged 60 years and over with unexplained non-visible haematuria and either dysuria or a raised white cell count on a blood test.
Consider a non-urgent referral for bladder cancer in people aged 60 years and over with recurrent or persistent unexplained UTI.[43]
Women under 65 years (without a catheter)
Ask if the patient has any of these key symptoms or signs of UTI:[4][49]
Dysuria
New nocturia
Be aware that new nocturia may be a sign of other problems, such as urinary retention and diabetes.
Cloudy-looking urine
Diagnose a UTI on the basis of 2 of the 3 key symptoms being present, or 1 symptom with a dipstick positive for nitrites or leukocytes and positive for red blood cells.[4]
If women have all 3 of these key symptoms, the probability of a UTI is 82%.[49] If women have 2 or more key symptoms the probability of a UTI is 74%, and with 1 key symptom the probability is 68%.[49]
If the patient has none of the 3 key symptoms, a UTI is less likely: ask about other severe urinary signs or symptoms, including urgency, frequency, visible haematuria, and suprapubic tenderness.[4]
Note that the Scottish Intercollegiate Guidelines Network guideline on management of suspected bacterial lower urinary tract infection in adult women considers dysuria, frequency, urgency, visible haematuria, or nocturia to be the key symptoms and recommends making a diagnosis on the basis of 2 or more of these symptoms plus, in women under 65, a dipstick positive for nitrite.[2]
Urgency is a common symptom of UTI, but it can also be a sign of an overactive bladder.[35]
Ask the patient if she is pregnant.
Consider the risk of preterm delivery in pregnant women as this is associated with UTI in pregnancy.[42]
Call the on-call obstetric team for advice if there are any signs of preterm labour such as abdominal pain, vaginal bleeding, or premature rupture of the membranes.
Ask the patient if she has a vaginal discharge, to exclude vaginal causes of urinary symptoms.[4] Do not diagnose a UTI in the presence of a combination of new onset vaginal discharge or irritation, even if the urinary symptoms of dysuria, frequency, urgency, visible haematuria, or nocturia are also present.[2]
Ask about possible urethral causes of urinary symptoms:[4]
Are symptoms worse after sexual intercourse or use of possible irritants?
If so, this suggests urethritis rather than a UTI.[50]
Ask about genitourinary signs of menopause (e.g., vulvovaginal atrophy, dryness, burning, irritation).
Evidence: Key symptoms for diagnosing UTI
Three key symptoms or signs (dysuria, new nocturia, and urine cloudy on examination) are independently predictive of UTI in women aged 18 to 70 years.[49]A combination of at least 2 of these can be used to diagnose UTI with a high positive predictive value.[49] However, the negative predictive value is poor.[49]
Public Health England, in its 2019 quick reference tool for the diagnosis of UTI in primary care, recommends that if women aged under 65 years have at least 2 of the 3 key symptoms or signs (dysuria, new nocturia, or cloudy urine) then a presumptive diagnosis of UTI can be made and, where appropriate, empirical antibiotics prescribed, without the need for urine dipstick or culture.[4]
This recommendation is based mainly on a 2010 study validating the sensitivity and specificity of urine dipstick and clinical scores.[49]
The study included 434 women (age 18-70) with suspected UTI (usually based on a history of dysuria and frequency) and no vaginal discharge. Confirmation of infection was by laboratory cultures. For the 431 women for whom clinical information was available:
Urine cloudy on examination was found to be the most reliable independent indicator of infection (positive likelihood ratio [LR] 1.8; negative LR 0.7; adjusted OR 2.5, 95% CI 1.6 to 3.9).
Dysuria, rated as a moderately severe problem, was also an independently predictive variable (positive LR 1.4; negative LR 0.7; adjusted OR 2.00, 95% CI 1.3 to 3.0).
Moderately severe nocturia and offensive smelling urine on examination were not found to be independently predictive. However, “any nocturia” was predictive (positive LR 1.2; negative LR 0.7; adjusted OR 1.60, 95% CI 1.0 to 2.6), and therefore the original score was modified to look at the performance of these 3 key symptoms/signs (any dysuria, any new nocturia, cloudy urine).
The greatest accuracy was achieved using a cut-off of at least 2 symptoms: sensitivity 80%, specificity 46%, positive predictive value 74%, and negative predictive value 54%, resulting in 69% of women being correctly classified.
The study noted the particular problem with poor negative predictive values.
Women over 65 years (without a catheter)
Check for local signs or symptoms of a UTI, including new-onset dysuria, incontinence, or urgency.[4]
Check for new symptoms of dysuria, or 2 or more of the following:[4]
Pyrexia
New frequency or urgency
New incontinence
New or worsening delirium or debility
New suprapubic pain
Visible haematuria.
Check for other non-specific signs of infection, such as delirium or loss of diabetic control.
Consider other causes of symptoms.
Check for other causes of delirium, if present, or if delirium or debility are the only symptoms.[4]
Check all patients for 2 or more localised symptoms/signs of:[4]
Respiratory tract infection
Gastrointestinal tract infection
Skin and soft tissue infection.
Ask about signs that might suggest menopause rather than a UTI, such as:[51][52]
Vulvovaginal atrophy
However, recurrent UTI may be a symptom of vaginal atrophy. Changes caused by oestrogen deficiency may predispose the urinary tract to infection.[53]
Dryness
Burning
Irritation.
Practical tip
Use the PINCH ME mnemonic to guide your review of the underlying causes of delirium:[4]
Pain
Other Infection
Poor Nutrition
Constipation
Poor Hydration
Other Medications
Environment change.
Women (any age) with a catheter
Thoroughly evaluate the patient as signs and symptoms are non-specific. Check for signs and symptoms compatible with catheter-associated UTI:[2]
New-onset or worsening fever
Rigors
Altered mental state
Malaise or lethargy with no other identified cause
Flank pain
Costo-vertebral angle tenderness
Pelvic discomfort
Acute haematuria.
Do not make a diagnosis of catheter-associated UTI based on the presence of pyuria. Do not use the presence or absence of odorous or cloudy urine to differentiate catheter-associated UTI from catheter-associated asymptomatic bacteriuria.[2]
Practical tip
In patients whose catheters have been removed, signs and symptoms compatible with UTI include:[2]
Dysuria
Urgent or frequent urination
Supra-pubic pain or tenderness.
Ask about previous episodes of bacteriuria.[55]
Take a sexual history.[4]
This might suggest a sexually transmitted infection (e.g., chlamydia or gonorrhoea) rather than a UTI.
Ask about risk factors. These vary according to the patient’s age.[26]
In premenopausal women, ask about:[26]
History of UTI[55]
Positive family history
Having a mother with a history of UTI is associated with a two- to fourfold increase in risk of recurrent UTI.[22]
Diaphragm use, especially when used with spermicide[55]
Pregnancy[36]
Carry out a pregnancy test if the woman is unsure.
Urinary tract infections are common during pregnancy. Infections and untreated asymptomatic bacteriuria during pregnancy have been associated with an increased risk of pyelonephritis, premature delivery, and fetal mortality.[36]
In postmenopausal women, ask about:[26]
Oestrogen deficiency
Recurrent UTI may be a symptom of vaginal atrophy.
Changes caused by oestrogen deficiency may predispose the urinary tract to infection.[53]
History of UTI[55]
Incontinence
Presence of a cystocele.
In older, institutionalised women ask about:[26]
Urinary catheterisation[2]
Incontinence
Medication, including recent antibiotics
Functional status.
Consider diabetes as a risk factor in any age group.[2][55]
Ask about current or history of renal tract stones. These can move into the ureter and cause obstruction.
Consider urethral stricture or stenosis. A previous catheter could have led to these.
Ask about any other anomalies of the ureter or urethra, which although rare, may lead to an obstruction.
Ask women with a catheter how long it has been in place. The duration of catheterisation is an important risk factor for the development of catheter-associated UTI.[2]
Check vital signs, including temperature, blood pressure, heart rate, and respiratory rate, looking for signs of systemic illness or sepsis.
Palpate the abdomen for flank or suprapubic tenderness and an abdominal or pelvic mass. A poorly emptying bladder may be palpable and is a risk factor for infection.
Check for blockage in patients with a catheter.[4]
Women under 65 years (without a catheter)
In women under 65 years, obtain a urine sample for culture, dipstick, and visual assessment.[4]
Visual assessment of the urine
Make a visual assessment of the urine to determine a cloudy or turbid appearance.
Cloudy urine is 1 of the 3 key signs and symptoms for diagnosing a UTI.[4] However, assessment of visual appearance of the urine is prone to observer error.
Urine dipstick
Perform a urine dipstick test in women under 65 years with urinary tract symptoms who have:[4]
Only 1 of the 3 key signs or symptoms (dysuria, nocturia, or cloudy-looking urine).
None of the 3 key signs or symptoms but other severe symptoms (urgency, frequency, visible haematuria, or suprapubic tenderness).
Note that the Scottish Intercollegiate Guidelines Network guideline on management of suspected bacterial lower urinary tract infection in adult women advises that a dipstick test should be performed in women under 65 who have 2 or more of the following urinary symptoms: dysuria, frequency, urgency, visible haematuria, nocturia.[2]
Practical tip
A urine dipstick test looks for positive leukocytes or nitrites to indicate a UTI. Organisms such as Escherichia coli or Klebsiella, Enterobacter, Proteus, Staphylococcus, or Pseudomonas species reduce nitrate to nitrite in the urine, therefore the presence of nitrite on a urinalysis is an indicator of a UTI.[56]
If the urine dipstick is:[4]
Positive for nitrites or leukocytes, and positive for red blood cells:
UTI is likely
Send urine for culture in cases where antibiotic resistance is likely
Positive for leukocytes only:
UTI is as likely as other diagnoses
Review time of specimen (morning is best)
Send urine for culture
Consider other diagnoses
Negative for nitrites, leukocytes, and red blood cells:
UTI is not likely
Do not send urine for culture
Consider other diagnoses.
If the dipstick result is negative but the symptoms suggest a UTI, the probability of disease is still relatively high.[49]
Urine sample for culture
Send a midstream, clean-catch urine specimen for culture if the patient has:[4]
2 or 3 of the 3 key diagnostic symptoms (dysuria, new nocturia, or cloudy-looking urine) and there is a risk of antibiotic resistance
1 of the 3 key diagnostic symptoms and a dipstick test that is positive for nitrite or leukocyte and red blood cells, making a UTI likely, and there is a risk of antibiotic resistance
1 of the 3 key diagnostic symptoms, and a urine dipstick that is positive for leukocytes and negative for nitrite, making a UTI equally likely to another diagnosis
None of the 3 key diagnostic symptoms but other severe urinary symptoms and a urine dipstick that is positive for nitrite or leukocytes and positive for red blood cells, and there is a risk of antibiotic resistance (UTI likely)
None of the 3 key diagnostic symptoms but other severe urinary symptoms and a urine dipstick that is positive for leukocytes and negative for nitrite, making a UTI equally likely to another diagnosis.
Do not interpret culture results in isolation. A growth of 10 7 to 10 8 colony-forming units (CFU)/L (10 4 to 10 5 CFU/mL) is usually used as a threshold for UTI, but take the patient’s symptoms into account.[4]
Lower counts can also suggest UTI, particularly if the patient is asymptomatic or has a single organism infection.[4][54]
White blood cells indicate urinary tract or urethral inflammation (>10 7 WBC/L) or may indicate colonisation in older people.[4]
Consider sending a repeat sample if mixed growth or epithelial cells are present in a symptomatic patient.[4][35]
Refer patients with persistent haematuria to a urologist after resolution of UTI.[4]
Consider Chlamydia trachomatis or other vaginal infections in patients with sterile pyuria.[4]
In pregnant women, always send a urine sample for culture.[4]
Practical tip
Advise women on how to collect a midstream, clean-catch urine sample, as the quality of the sample affects the ability to detect bacteria.
Collecting a midstream urine sample and holding the labia apart may help reduce contamination, but if not possible the sample can still be sent for culture.[4]
Advise against cleansing the area with antiseptic, as bacteria may be inhibited.
Women over 65 years (without a catheter)
Send a urine culture, ideally before giving antibiotics, in all patients aged over 65 years with likely UTI.[4]
There is a greater risk of antimicrobial resistance in older patients.[4]
Consider a urine dipstick in patients over 65 years as a supplement to the urine culture and to detect red blood cells.
Public Health England notes that urine dipstick results become more unreliable with increasing age over 65 years, and does not recommend them for adults aged over 65 with suspected UTI.[4]
Women (any age) with a catheter
Send a urine sample for culture, ideally before giving antibiotics, in catheterised patients who present with fever.[57][2]
Take the sample from the catheter, via a sampling port if provided, using an aseptic technique.[57]
If the catheter has been changed, obtain the sample from the new catheter.[57]
If the catheter has been removed, obtain a midstream sample of urine.[57]
Note for the lab that you suspect catheter-associated infection and any antibiotic prescribed.[57]
Practical tip
Catheter-associated UTI is defined as the presence of symptoms or signs compatible with a UTI in people with a catheter with no other other identified source of infection, plus significant levels of bacteria in a catheter or a midstream urine specimen when the catheter has been removed within the previous 48 hours.[57]
Do not use dipstick testing or urine microscopy to diagnose UTI in patients with catheters.[2]
Symptomatic UTI cannot be differentiated from asymptomatic bacteriuria on the basis of urine analysis by dipstick tests or by microscopy. Pyuria is common in catheterised patients and its level has no predictive value.[2]
Do not order imaging routinely to diagnose UTI.
Uncomplicated UTIs do not usually need imaging unless they are recurrent.
Request imaging if treatment has not been successful or in patients with unusually severe or persistent symptoms.[58]
Use ultrasound to rule out urinary tract obstruction in women with uncomplicated pyelonephritis and a history of urolithiasis, renal function disturbances, or a high urine pH.[1]
Consider measuring post-void residual in women with recurrent UTIs or in unwell women with suspected UTI.
Poor bladder emptying may be a cause and UTIs may continue to occur until this is resolved.
In hospital consider contrast-enhanced computed tomography (CT) in unwell patients, for example, if the patient remains febrile after 72 hours of treatment, or immediately in any patient with worsening clinical status.[1]
Consider non-contrast CT to identify stones, particularly if obstruction is identified on ultrasound scan.
In pregnant women, use ultrasound imaging preferentially to avoid radiation risk to the fetus.[1]
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