Investigations
1st investigations to order
urinalysis
prostate-specific antigen (PSA)
Test
Use PSA testing in appropriate circumstances and with shared decision-making. It is generally not recommended in men over the age of 70, or with a life expectancy less than 10-15 years. Counsel patients carefully about the potential consequences of PSA testing.[22][23][24][32] Increased PSA may suggest the presence of underlying prostate cancer or prostatitis.
A serum PSA test may be helpful in assessing treatment options and in decision-making (as an approximate indicator of prostate size), or if a diagnosis of prostate cancer would change management.[17][18]
Result
elevation greater than age guideline
symptom score questionnaire
Test
Assess the nature and severity of the patient’s symptoms, and the impact on their quality of life using a validated symptom score questionnaire. This should be completed in the initial work-up and can be used for re-evaluation during and after treatment.[17][18]
The International Prostate Symptom Score (IPSS), a self-administered questionnaire with 8 questions (7 questions on symptoms and 1 question on quality of life) is most commonly used.
Other questionnaires include the International Consultation on Incontinence Questionnaire for Male LUTS (ICIQ-MLUTS), the Danish Prostate Symptom Score (DAN-PSS) and the Symptoms of Lower Urinary Tract dysfunction Research Network (LURN-10). The LURN-10 is closely correlated to the IPSS but includes additional symptoms (incontinence and bladder pain).[25][26][27] ICIQ: International Consultation on Incontinence Questionnaire Male Lower Urinary Tract Symptoms Module (ICIQ-MLUTS) Opens in new window
Result
IPSS score of 0 to 35 to define severity of symptoms: mild score: 0 to 7; moderate score: 8 to 19; severe score: 20 to 35. Quality of life (bother score) scored from 0 to 6
frequency/volume chart and voiding diary
Test
If the patient has significant nocturia, ask them to complete a frequency/volume chart and voiding diary for at least 3 days. Recording the volume and time of every void, and additional information such as fluid intake, symptoms, and use of pads, can be a useful tool to objectify symptoms and detect polyuria (>3 litres of urine in 24 hours).[18][20]
Result
diary of frequency and volume of voiding
Investigations to consider
ultrasound
Test
Consider transrectal or transabdominal ultrasound to accurately assess the size and shape of the prostate before treatment with a 5-alpha-reductase inhibitor or to inform choice of surgical interventions.[17] Transrectal ultrasound is more accurate than transabdominal measurement and is the most commonly used modality for imaging the prostate.[18][31]
Ultrasound is the preferred method of assessing bladder volume in post-void residual (PVR). A measurable PVR may be seen in bladder outflow obstruction due to BPH.[31]
Result
prostate size and shape; PVR volume
CT or MRI abdomen/pelvis
Test
Consider using preexisting CT or MRI imaging scans, preferably obtained within the preceding 12 months, to accurately assess the size and shape of the prostate before treatment with a 5-alpha-reductase inhibitor or to inform choice of surgical interventions.[17]
Result
prostate size and shape
cystoscopy
Post-void residual (PVR) assessment
Test
Perform before surgical intervention for LUTS attributed to BPH.[17] This is helpful for post-operative management and assessing the success of surgical interventions.
Consider PVR measurement as an optional study in the initial management of patients where medical therapy is being considered; a PVR can help to assess the ability of the bladder to empty at baseline, identify severe urinary retention, and/or indicate detrusor dysfunction.[17][18]
Using a PVR threshold of 50 mL, diagnostic accuracy of PVR measurement has a positive predictive value of 63% and a negative predictive value of 52% for bladder outlet obstruction.[18]
Result
elevated urine retention PVR volume
uroflowmetry
Test
Consider uroflowmetry (a non-invasive measure of peak urinary flow rate) in patients with moderate to severe BPH, particularly before surgical intervention for lower urinary tract symptoms attributed to BPH.[17][28]
Low peak urinary flow rate may be due to bladder outlet obstruction, detrusor underactivity, or an underfilled bladder. A peak urinary flow rate of 10 mL/second has a specificity of 70% and a sensitivity of 47% for bladder outlet obstruction (BOO), and a peak urinary flow rate of 15 mL/second has a specificity of 38% and a sensitivity of 82% for BOO.[29]
The diagnostic accuracy of uroflowmetry for detecting BOO varies considerably, and specificity improves with repeated flow rate testing.
Result
less than 15 mL/second
pressure flow urodynamic studies
Test
Considered before surgical intervention for LUTS attributed to BPH when there is diagnostic uncertainty.[17] Pressure flow studies provide the most complete means of determining the presence of bladder outlet obstruction (BOO) but most patients can be managed and treated surgically without them. Pressure flow studies can be helpful in distinguishing BOO from detrusor underactivity and may be helpful in counselling patients about their individual risk for improvement following treatment.[30]
A synchronous pressure flow study that looks at the pressure flow relationship, with rises in pressure during filling suggesting bladder overactivity (detrusor overactivity) or elevated voiding pressures combined with a reduced flow, can be useful for patients for whom surgery may be contemplated or if symptoms are persistent following invasive procedures.[28]
Result
abnormal bladder pressure, abnormal bladder voiding
assessment of renal function
Test
European guidelines advise assessment of renal function via measurement of serum creatinine or estimated glomerular filtration rate (eGFR) in the following circumstances: if renal insufficiency is suspected; in the presence of hydronephrosis; or in anticipation of surgical intervention.[18]
Renal insufficiency is not commonly related to isolated BPH.
Result
creatinine is elevated with impaired renal function; eGFR may be reduced in chronic kidney disease stages 3-5 (<60 mL/min/1.73 m²)
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