All definite haematuria whether microscopic or macroscopic requires investigation to exclude serious underlying causes such as urinary tract cancers once benign causes of microscopic haematuria have been excluded. Benign causes of microscopic haematuria include:
- Vigorous exercise or injury to the urinary tract
- Urinary tract infection
- Recent urinary tract procedures or surgery
The presence of persistent haematuria on retesting of the urine after benign causes are excluded means that further investigations are needed.
Patients on anticoagulants (blood thinning medications) also require investigation as anticoagulants are more likely to reveal rather than be the cause of haematuria.
Initial investigation of Haematuria
The initial investigations for haematuria include:
- Blood tests for:
- Kidney function and blood examination
- Potentially PSA testing in men (after individual counselling)
- Urine testing
- MSU - mid-stream urine testing for infection
- Urinary cytology - to look for abnormal or cancer cells in the urine
- Urinary tract imaging which may include:
- Renal ultrasound
- CT scanning with CT IVP
- Cystoscopy is required even when other tests such as urinary tract imaging and urinary cytology are normal as it is the only way to definitively investigate for abnormalities of the bladder lining such as bladder cancer.
- Cystoscopy can be performed as a “flexible cystoscopy” using local anaesthetic gel which is a procedure that can be performed in the doctor’s rooms (i.e. not requiring hospitalisation)
- Cystoscopy can also be performed in hospital with sedation or a general anaesthetic called a “rigid cystoscopy”. Additional procedures such as biopsy of abnormalities within the bladder lining can be performed at the same time as the cystoscopy if it is performed under anaesthesia.
Cystoscopy is mandatory in:
- All patients with macroscopic haematuria
- Patients with asymptomatic microscopic haematuria older than 35 years
- Patients with symptomatic microscopic haematuria
- Patients with risk factors for urological malignancy
Other tests for Haematuria
More specialised testing may be required in some cases depending on the level of haematuria and risks factors for urinary tract malignancy or medical conditions that can affect the kidneys. These tests include:
- Renal angiography – specialised X-rays looking for abnormal blood vessels within the kidney which can cause haematuria
- Ureteroscopy and retrograde pyelography – These are minimally invasive surgical procedures using telescopes inserted into the upper urinary tract to investigate for cancers within the urinary drainage system
- Renal biopsy – looking for medical conditions which can affect the kidneys such as glomerulonephritis
Choice of Urinary Tract Imaging (X-Rays) in Haematuria
- Renal tract ultrasound is often used to assess the kidneys and upper urinary tract in patients with microscopic haematuria who are younger (under the age of 40 years) and at low risk of urinary tract cancers. Ultrasound does not involve radiation or have a risk of contrast (the intravenous dye used in CT scanning) reaction or allergies, but is less sensitive and less accurate in detecting kidney cancers, ureteric cancers and bladder cancers compared to CT scanning.
- CT scanning without the use of intravenous contrast (CT KUB) is the current gold standard for detecting stones (calculi) within the kidneys and ureters (tubes draining the kidneys to the bladder).
- CT scanning with use of intravenous contrast (called a CT IVP – CT intravenous pyelogram) is used to give a precise picture of the kidneys and drainage systems of the kidneys and is the preferred form of X-ray to detect cancers in the urinary tract. CT IVP is the imaging of choice when macroscopic or visible haematuria is present as it is more sensitive in detecting urinary tract cancers and other pathologies.
Indications for Urological referral
Referral to a Urologist is recommended in all patients with:
- Macroscopic (visible) blood in the urine
- Persistent microscopic (invisible) blood in the urine
- Abnormal urinary cytology
- Patients with irritative bladder symptoms with haematuria (i.e. frequency, burning with urination)
- Recurrent urinary tract infections
Indications for referral to a Nephrologist
A Nephrologist is a physician specialising in medical conditions affecting the kidney. Indications for referral to a Nephrologist for microscopic haematuria include:
- Patients in whom Urological causes of haematuria have been excluded
- Patients with impaired or worsening kidney function
- Patients with significant protein found in the urine on urine testing
- Isolated haematuria with hypertension (high blood pressure) in patients under the age of 40 years.
Follow up of patients in whom a definite diagnosis for their Haematuria is not found
If a definite diagnosis of the cause of haematuria is not made despite the above investigations, investigations should be repeated whenever gross or macroscopic haematuria occurs.
Patients with persistent microscopic haematuria without any urinary symptoms should be monitored for the development of:
- Urinary symptoms e.g. frequency, difficulties with urination, pain on urination
- Visible haematuria
- Progressive increase in level of microscopic haematuria
- Development of significant protein in the urine
- Progressive impairment in kidney function
- Hypertension (or high blood pressure) which is usually unrelated to minimal microscopic haematuria in older people
Follow up should include yearly urine testing (performed by the patient’s GP) with regular monitoring of kidney function and blood pressure for at least 3 years.