Blood in Urine – Causes and Tests

by | Tests and Investigations

Blood in Urine

1. Causes of Blood in Urine

Blood in the urine is something that always needs to be tested. We call it hematuria. And the most important thing that we need to rule out, when a patient presents with that, is any sort of cancer that might be affecting the urinary tract. So that might be anything from the kidney right down to the urethra.

Kidney Cancer

One of the commonest of course is kidney cancer. You can get cancer rising in the bladder, or in fact any lining of the urinary tract along the whole way. Prostate cancer rarely presents with blood in the urine, but can. So they’re really the main diagnosis that we need to rule out. Sometimes however, you can get blood in the urine with a cluster of other symptoms. These include painful urination, or a fever. That situation is very different because it’s far more likely to be due to an infection. It could also be due to an urinary tract infection. But when we see blood in the urine, without those other infective symptoms. We must rule out any sort of cancer.

Kidney Disease

Another potential cause of blood in the urine, can be kidney disease. Sometimes the actual filtering systems within the kidney, the glomeruli, can bleed and you can have a condition called, glomerulonephritis. This needs to be treated as well. Sometimes, blood in the urine, or hematuria, can be visible to the patient, what we call that, gross hematuria. And that’s what present or approach us present with.

Other times however, they might have had a urine test done for another reason altogether. And it was only during this test that blood cells have been found under the microscope. This is then called microscopic hematuria. They’re really quite different in terms of their clinical importance. Microscopic hematuria is actually not that uncommon. Again, we still need to rule out any underlying disease. However, sometimes we’ll see very small elevations of red blood cells in the urine. These elevation sometime turn out to be nothing at all. But our job as urologists is certainly to diagnose. We must identify if there is any sinister cause of that blood in the urine.

2. Tests to Determine Causes of Blood in Urine

Urine Test

The first test for blood in the urine is of course a urine test. If the patient is presenting to the GP with blood in the urine, then the GP will test that urine. This is to confirm that there are red blood cells and to rule out potentially any infection. Sometimes the actual shape of the red blood cells under the microscope can give us clues about the potential diagnosis. For example, if the shape has been altered of the red blood cells, then it’s more likely to be due to disease of the filters within the kidney. But if the shape has not changed then it may be more likely to be due to a tumour, such as a kidney cancer for example.

Seek Regular Follow Up

You can have episodes when you see blood in the urine, and it’s quite obviously red, and then a few days later you might get a urine test and actually have no red blood cells in there at all. I think it’s important that if that occurs to actually not to be re-assured by that. I’ll give you an example. If a patient has a tumour in the bladder it might bleed one day, causing visible blood in the urine. Then it will stop bleeding a few days later. Now if it stops bleeding, it hasn’t gone away, it’s just stopped bleeding. So if a patient has blood in the urine and then it stops, they must still see a doctor. The bleeding must be investigated.

CT and Imaging Tests

The tests for blood in the urine once you’ve actually tested the urine are imaging. This might take the form of a urinary tract ultrasound. This is a totally non-invasive test which can look at the kidneys, and the bladder. It can also assess the prostate in men. However if there is nothing found on that but there’s even more suspicion, then sometimes we’ll get a CT scan. A CT scan is much more sensitive at picking up smaller tumours, for example. You will be injected with some contest or dye into your vein. The contrast or dye, will then be filtered by the kidneys and will light up the urinary tract system. The CT scan detects this and gives us a really good picture of the kidney tracts.


Cystoscopy is another test you need to have done. We will use this to look inside the bladder, with a scope, because sometimes you can get a very small or flat lesion arising from the bladder, such as a flat bladder cancer, that you can’t actually see on imaging. So we have to directly eyeball it with a scope.


There are also some other urine tests that we’ll occasionally do, which are not just confirming for whether there’s blood in it or not, but actually looking for abnormal, or cancer cells within the urine, that’s called urine cytology. And if we do that we’ll often get three of them because the shedding of tumour cells from a tumour within the urinary tract is quite intermittent. For example, if we just did one of those then the tumour might not be shedding any of it’s cancer cells that day, so we tend to get them on different days.

Associate Professor Dr. Jeremy GrummetUrological surgeon and Director of Clinical Research in Urology at Alfred Health. Member of Australian Urology Associates private practice group