Hematuria

You will find information on hematuria which is not associated with recent urologic surgery. For information on how to manage hematuria associated with recent surgery, please check the Surgery section. If the hematuria is associated with prior or recent urological surgery (e.g. prostate or stone surgery) the causes and evaluation are often different than what is presented here.

Background

Hematuria is one of the most common reason for urological referral. Blood in the urine may be:

MICROSCOPIC/NONVISIBLE hematuria: requires a microscope to be detected and cannot be seen with the naked eye but detectable.
GROSS/VISIBLE hematuria: visible to the naked eye, sometimes accompanied by clot. Blood may be bright red, dark red, brown or tea coloured.

While hematuria can be a sign of problems with the filtration/concentration functions of the kidney, the most common causes by far is bleeding from the collecting system or renal parenchyma. The collecting system is comprised of all the pipes and tubes through which urine drains once it has been formed by the microscopic filters and tubules within the meat of the kidney (i.e. the parenchyma). This is the reason why urologists rather than nephrologists evaluate hematuria.

IMPORTANT:

The evaluation of any blood in the urine is one of ‘exclusion’ rather than ‘assumption’. Cancers, especially bladder cancer, must always be excluded even if another potential cause is identified. Many patients understandably would like to avoid investigations such as cystoscopy and may attempt to justify this by explaining away the blood by pointing out other conditions that might explain for the hematuria (e.g. kidney stones, anticoagulants or eating particular foods). This line of thinking is discouraged since it is possible to have bladder cancer in addition to less serious conditions. Fortunately, the vast majority of patients with non-visible (microscopic) hematuria do not have cancer but this cannot be stated with certainty unless the appropriate testing is done. For the minority that have bladder cancer, a prompt diagnosis will result in a more favourable outcome whereas a delay in the diagnosis of a bladder cancer may be life-threatening. While there may be a number of clinical features that make bladder cancer less likely, the safest and most prudent approach is to follow the recommendations from your urologist and the medical professional societies that provide evidence-based guidelines.

Cancers may bleed intermittently. Never ignore even a single episode of blood in your urine - see you family physicians as soon as possible. Never assume that the hematuria is the result of blood thinners (e.g. anticoagulants or anti platelets). Hematuria should be assumed to be cancer until proven otherwise. If you have cancer, you will benefit from early detection.

Causes

Hematuria, especially gross hematuria, can be a presenting sign of BLADDER CANCER or KIDNEY CANCER and should never be ignored.

There are literally hundreds of possible reasons for hematuria, but only a handful of worrisome causes that need to be ruled out. The most common causes for hematuria are urinary tract infections, kidney stones, benign growth of the prostate and urothelial cancers (especially involving the bladder). In many cases, a cause will not be identified despite a complete and thorough evaluation and this is referred to as idiopathic benign hematuria.

A substantial adult population has microscopic hematuria at any given time - the number varies from about 1 in 30 to 1 in 3 adults depending on the population being studied. Hematuria is much more common with age. The risk of serious conditions is highly dependent on risk factors and will vary between roughly 1 in 100 to 1 in 10. In patients with visible blood the risk of bladder cancer may be as high as 1 in 2 for those patients with a history of cigarette smoking. The major risk factors for bladder cancer (the most common and serious cause of hematuria) or a kidney cancer (a serious but less common cause of hematuria) include:

Visible blood (Gross hematuria)
Increasing age (especially over age 50)
Male gender
Caucasian ethnicity
Smoking history
Certain exposures: e.g. specific occupational exposures, chemotherapeutic agents, or radiation

Diagnosis & Evaluation

Depending on your situation, your urologist may recommend a number of tests to rule out a potentially important cause. The general diagnostic approach is to tailor the evaluation to exclude serious causes as best as possible. The evaluation is tailored to the patient's risks and clinical evaluation. This always starts with a history and physical examination followed by investigations targeted at the upper tracts (kidney, renal pelvis and ureters) and lower tracts (bladder and urethra). The commonly used tests include:

Cystoscopy: required in all patients with rare exception* - this is the only test that can reliably check for bladder cancer.
Urine tests
1. Urine microscopy: only a single test with ≥3 red blood cells (RBC) is necessary to initiate evaluation. A dipstick can show hemoglobin (hemoglobinuria) but this is not the same as hematuria. The causes of a positive hemoglobinuria on dipstick include the presence of red blood cells, hemoglobin or myoglobin. The later two conditions are not evaluated by a Urologist.
2. Urine cytology: this is not a recommended core investigation for hematuria. It is not specific or sensitive enough to exclude urothelial cancer. Many patients are under the incorrect assumption that a urine test that is ‘negative for cancer’ means that they do not have bladder cancer or that a cystoscopy is unnecessary.
3. Consider urine to creatinine ratio if there is protein in the urine dip.
Blood Tests: creatinine/eGFR to check kidney function. PSA for males if appropriate. Referral to nephrology is a urological cause is not identified.
Imaging: imaging required to evaluate the upper tracts (kidneys, renal pelvis and ureters). The type of test is up to the discretion of the Urologist but in general it is usually ultrasound for microhematuria and CT IVP for gross hematuria or those with higher risk of upper tract cancers.

*Cystoscopy is the most important test because it is the only test which can reliably exclude the presence of bladder cancer. Cystoscopy will detect over 99% of bladder cancers. There are few exceptions to skipping the cystoscopy - in general, the only patients who do not require cystoscopy are females less than about 35-40 years of age with clear evidence of another cause (for example, bladder infection).

Treatment

The treatment of hematuria is directed at the cause. You may find more information on the common causes of hematuria such as kidney stones, benign prostatic enlargement and bladder cancer on the Urologic Conditions page.

Hematuria in of itself can produce a number problems such as anemia or the development of clots in the upper urinary tract which can produce obstruction (with symptoms very similar to kidney stones) or in the lower urinary tract. In the vast majority of people, the amount of blood loss is minimal but can appear large simply because the blood has been diluted in urine. Blood clot which forms in the bladder can obstruct the bladder outlet and urethra and cause urinary retention. This may require a catheter to flush the blood out. In order to reduce the chances of blood clot formation, increased fluid intake and frequent urination is advised.

Follow-Up

If a specific cause was found during testing, your urologist will provide advice to address the particular condition.

If no cause for the hematuria is identified (so called 'idiopathic hematuria'), there are several options. None of the guidelines from the American Urological Association or Canadian Urological Association specify what the optimal follow-up is but in general, the follow-up should be tailored to the patient. Patients who had very little risk of having a serious condition to start (for example, younger patients, females, those with no history of smoking) may not require any follow-up. Those patients who remain at increased risk of developing a serious condition (especially cancer) may require a repeat scope, urine tests and even imaging and/or cystoscopy. Some patients with idiopathic hematuria may have kidney conditions such as IgA nephropathy or thin basement membrane disease but in the absence of an issue with the kidney function (checked with a serum creatinine) a referral to a nephrologist is unnecessary.

The current 'expert' opinion/consensus is:

Asymptomatic microhematuria with a normal evaluation: no follow-up if very low risk, alternatively annual urine analysis x 2 years
1. If no blood for 2 years, discharge from follow-up.
2. If blood persists, consider repeat cystoscopy and imaging within 3-5 years.
Gross hematuria with a normal evaluation: repeat a urine analysis yearly for a couple of years.