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Complete Guide To The Causes Of Blood In Urine In Males & Females (2019)

Complete Guide To The Causes Of Blood In Urine In Males & Females (2019) undefined
Table Of Contents

You may be shocked and concerned if you find blood in your urine. You may, however, be even more surprised if I say the condition is actually not uncommon. It can happen to both males and females, in both children and adults.

There are various causes of blood in urine. It could be cancer or a simple infection. That said, you should never ignore the condition. In some cases, hematuria can be a sign of a more serious disease. It is always important to figure out the cause of the bleeding.

I am writing this article to discuss everything you need to know about the condition. I am going to talk about its cause, possible complications, and also the treatment options available in Singapore. Read on to find out more!

What is hematuria?


It is the medical term for blood in the urine. There are two main types:[1]

  • Gross/visible: blood that you see
  • Microscopic: blood that is found during urine lab tests

In both cases, blood loss is usually not heavy. Regardless, it is more important to think of the cause. It is important to know WHY there is blood in your urine. Up to 50% of all cases of visible blood in urine are caused by a certain underlying disease!

Is blood in the urine dangerous?


Most cases of blood in the urine are painless. But at times, they could be painful and come along with other symptoms.

Against common beliefs, visible blood with no pain in the urine is actually more alarming! This is because cancers along the urinary tract often have no symptoms in their early stages. Hematuria can be a symptom of:

  • Kidney,
  • Bladder, and
  • Prostate cancer

If you feel pain when you pee and find blood in your urine, it is likely due to a urinary tract infection (UTI). Otherwise, it might also be caused by kidney or ureter stones [1]. If you feel pain around your back and abdomen it is best to go for a consultation as soon as possible!

My urine is blood-red!


Sometimes reddish or dark brown urine is not caused by blood. These uncommon cases are called pseudo-hematuria. They can be caused by [2]:

  • Reddish foods: dragonfruit, beet, rhubarb and certain berries
  • Certain medications: seizure (Phenytoin), laxatives (Senna), urination pain (Urogesic)

Do not assume every reddish urine is pseudo-hematuria. If your urine is reddish, it is best to visit a doctor. You should also get a urine test to check for the presence of blood in urine. This is very important to detect and treat possible underlying conditions before they continue to develop.

Invisible blood in the urine


Often times, blood in the urine is not visible to the naked eye. However, traces of blood in urine can be found in a urine dipstick test. You might take this test as a follow up for other chronic diseases like hypertension or diabetes. It might also just be another routine health screening.

This is termed microscopic hematuria [1]. In most cases, it is not linked to any other urinary symptoms.

That said, it could also be an early sign of an underlying condition that may cause gross hematuria in the future. On detailed check-up, as many as 5% of those affected are found to have urinary stones or cancer. This risk is higher in older men and smokers. [3]

At times, a urine dipstick can be falsely positive for blood. This is why if your dipstick is positive for blood, I would recommend that you request a repeat test with a microscopic examination! This is to confirm the presence of blood in your urine. If this result is again positive, you should visit a specialist for further investigations.

Just because the blood is microscopic, it does not mean that the cause is minor. I have found large bladder cancers in patients that only had microscopic hematuria and no other symptoms. Please always be alert!

What are the causes of blood in urine?

There are various causes of hematuria:

  • Urinary tract infection (UTI) [4]


    This occurs when there is bacterial growth along the urinary tract. This includes the kidneys, ureters, bladder, and urethra. The symptoms vary depending on where the infection is. It can cause:

    • Pain while urinating
    • Frequent urge to urinate
    • Back pain
    • Nausea
    • Loss of appetite
    • Fever
    • Blood in urine

    UTI is a common condition that affects both men and women. That said, women are much more prone to the infection. The risk also increases with sexual activity and age.

    It is expected that 40% of women will have the condition at some point in their life. In Singapore, 4% of young women have UTI. For women above 50 years old, the incidence rate rises to 7%.

    Most cases of UTI are ‘simple’ and can be treated with antibiotics. That said, some people are more prone to complicated UTIs and may require further treatments. It is best to consult your doctor and get the exact diagnosis before getting treatments.

  • Urinary tract stones [5]


    At times, the minerals in your urine can form crystals on the walls of your kidneys. These crystals can travel along the urinary tract and form hard stones. It can cause symptoms such as:

    • Pain around the lower abdomen and groin
    • Blood in the urine
    • Nausea
    • Fever
    • Discoloured urine
    • Difficulty passing urine

    You might have to get a CT scan, ultrasound and a urine test to get the full diagnosis. Depending on the diagnosis, treatment may include oral medication and even surgery.

    Kidney stones can be prevented if you keep to a balanced and healthy diet. It is also important to stay hydrated at all times.

    Also read: How Our Diets Today Are Causing Kidney Stones

    If you feel any discomfort along your lower back and groin area, please do seek for treatment as soon as possible.

  • Tumours [6]

    This can happen anywhere along the urinary tract. Many patients with urinary tumours experience no symptoms during the early stages. This is why it is important to investigate further if you have blood in your urine!

  • Enlarged prostate [7]


    The prostate is just below the bladder and surrounds a part of the urethra. It is often enlarged in older men, aged 50 onwards. This is also known as benign prostatic hyperplasia (BPH). The symptoms are:

    • Difficulty passing urine
    • Frequent urge to urinate
    • Weak urine stream

    Though uncommon, there might also be blood in the urine. This is because large blood vessels may grow on the inner surface of the prostate. Note that in most cases, the blood is microscopic.

    Its risk factors include:

    • Age
    • Diabetes and heart diseases
    • Obesity
    • Family history

    If you suspect that you have BPH, please consult a doctor as soon as possible. There are different types of tests that you might need to take. You can ask your doctor to find out which ones you need.

  • Kidney Inflammation (Glomerulonephritis) [8]

    This refers to an inflammation of the kidneys’ filtering system. It is the second leading cause of renal failure in Singapore. Some common symptoms include:

    • Blood in the urine (microscopic)
    • Protein in urine
    • Leg swelling

    The condition may be caused by viral or bacterial infections. It can also be a complication of other immune system diseases or diabetes.

    The treatment really depends on the severity of your case. If you see any symptoms, please consult your doctor.

  • Vigorous exercise

    It is very rare, but it can happen. Some cases include:

    • Runner’s bladder [9]

      Research found that both gross and microscopic hematuria can be caused by active exercise. This is most common in cases of long-distance running. That said, it usually resolves itself within 48 to 72 hours.

      The theory is that when you run, the back of the empty bladder repeated hits the front part. This traumatizes the inner lining of the bladder and causes bleeding.

      Following that, a solution might be to avoid passing urine right before running. This will allow the bladder to be partially filled and cushion its walls from damage.

    • March hematuria (hemoglobinuria) [10]

      This occurs when red blood cells are found in the urine after repetitive impact on the body, especially the feet. The word “march” is used because the condition is commonly found in soldiers who have been marching for long periods.

      The repetitive impact causes red blood cells to burst. The red pigments are filtered in the kidney and cause the urine to turn a dark brownish colour.

Please do not ever assume that blood in your urine is caused by exercise. If you see anything abnormal with your urine, you should always visit a doctor. This is because oftentimes, there is already an underlying urinary tract injury. It is just worsened by the exercise.

 Ask Dr Lincoln Tan a Question

Do I need to visit the hospital if I see blood in the urine?


In some cases, hematuria can resolve spontaneously. That said, this does not mean that the underlying condition has been resolved. This is why even a single episode of visible blood in the urine needs to be assessed.

Hematuria can happen quite randomly. This is true even for cancer patients. Some patients reported only seeing blood once and thought that it had passed. The next time they saw it and got a full diagnosis, it is too late and the tumour has already progressed to a more advanced stage.

Often times, people think that blood in the urine is simply due to UTIs. This is especially in females as UTIs are very common [4]. That said, it might now always be the case!

Symptoms of UTIs include burning pain when passing urine and frequent urge to urinate. If you see blood in your urine accompanied by these symptoms then it makes sense to assume that it is caused by a UTI.

If it is painless, you should NEVER blame it on UTIs. While it may resolve after taking antibiotics, this may be a coincidence rather than proof that it was caused by a simple UTI.

You should note that bleeding caused by tumours is not constant! In most cases, it is intermittent and stops after that one incidence. A study found that 10% of people with visible hematuria have bladder cancer [11].

Differentiating this can be confusing. As a general guide, please just visit your doctor to make sure!

Contact Dr Lincoln Tan

Hematuria is a symptom of bladder cancer

Bladder cancer is more common in men. That said, women usually have a worse outcome [12].

Women tend to have a delayed diagnosis of bladder cancer. This is because patients and even doctors would first suspect UTIs as the cause of hematuria in women. As UTIs are very common, it does make sense to do so. That said, you should be alert if you have recurring UTIs. You should also take note if your hematuria does not resolve with antibiotics. In those cases, it is best to see a specialist to rule out the other causes!

On the other hand, people directly linked hematuria in men to cancers. Most men are then directly referred to urologists after just a single episode of visible blood. This is the best scenario! Early diagnosis is the best starting point to get a full recovery.

Male or female, you should really be alert if you see blood in your urine. It can be a UTI, a kidney stone, an infection, or even cancer. They only accurate way to find out is to go to the doctor!

Complications of blood in the urine


In most cases, blood in your urine is not an emergency situation. That said, you should always be alert!

You should go to the doctor if your urine has a very dark red colour. That is because the deep colour can be a sign of significant blood loss.

If the bleeding is significant, the blood may form clots. This can block urine flow from the kidney.

Though rare, the blood clot may also cause the inability to pass urine. This condition is called acute urinary retention (AUR). When this happens, a tube may have to be inserted to bypass the block [13].

If the bleeding is persistent, you can lose enough blood to become anaemic. In severe cases, sudden blood loss can also lead to low blood pressure and shock. This is very rare but it can be dangerous! If you experience hematuria for a long period or see a lot of blood in your urine, do visit your doctor.

How to prevent and treat blood in urine?


Hematuria can only be prevented and treated after its cause is diagnosed. This is because you would have to manage the underlying cause to prevent the symptoms.

As a general guide, you can prevent blood in urine by:

  • Staying hydrated
  • Stop smoking

In the next section, I will detail out some common causes and risk factors. You should take note of those factors to prevent the condition. Read on to find out more!

Am I at risk of hematuria?

Problems with clotting increase the chances of blood in the urine. This could happen in patients consuming blood thinners, or in those with blood diseases.

That said, it is important to rule out the underlying conditions that cause hematuria! Finding blood in urine is often a symptom of other diseases, some common ones include:

ConditionRisk Factor
Kidney cancer [14]
  • Cigarette smoking
  • Hypertension
  • Obesity
  • Dialysis
Bladder cancer [11]
  • Cigarette smoking
  • Second-hand smoking
  • Family history
  • Chemicals used in the textile, rubber, leather, dye, paint, and print industries
  • Long-term catheter
Urinary tract stones [5]
  • Low fluid intake
  • High sodium and protein intake
  • Obesity
  • Family or personal history
Urinary tract infection [4]
  • Low fluid intake
  • Blockages in the urinary tract
  • Enlarged prostate
  • Sexual activity
  • Family history
  • Menopause


How is the cause for hematuria diagnosed?


If blood is found in your urine, your doctor will ask for your detailed medical history. He/she will also ask about other symptoms that might point to a certain underlying cause. On top of that, your doctor will also check for risk factors such as family and smoking history.

You might be recommended to get another round of urine test. This will reconfirm the presence of blood and check for infections. For some men, a prostate-specific antigen (PSA) blood test may also be offered to check for prostate cancer.

Depending on your condition, you may be referred for CT scans and ultrasound to check for stones or tumours. If cancer is suspected, you will be referred to a urologist for a cystoscopy.

What is cystoscopy?


Even if your CT scans came out normal, you might still need a cystoscopy. This is because, in the early stages, cancer can be flat or very small and easily missed.

Cystoscopy is a diagnostic test done to check the lining of the bladder. It is done with a small flexible tube called a cystoscope. The cystoscope contains a camera and a light system. It is passed through the opening of the urethra in the penis.

The procedure lasts only 2 – 3 minutes and is usually done under local anaesthesia. Your urologist will introduce a gel into the urethra before the procedure. It is an outpatient treatment that can be done in the urologist’s office or in an endoscopy suite.

With this, doctors are able to check and identify tumours causing bleeding. Tissue samples can also be obtained and sent to test for cancer.

What if the cause of blood in urine is cancer?


Cancer is a huge concern and I understand that you may be scared. But do not skip consultations just because of that!

Every time I counsel my patients, I always tell them that if you do have cancer, finding them earlier is better. Early cancers of the urinary tract are usually curable! The treatments are also better tolerated and less disfiguring.

As an example, early bladder cancer can be removed with endoscopic surgery through the urethra. This leaves no scars on the body.

On the other hand, advanced stage bladder cancer may need chemotherapy. In some cases, patients also have to get surgical removal of the bladder. This will involve a large 15 cm incision at the abdomen. Doctors will then have to create a new tube (ileal conduit) from a part of your intestine to allow the urine to exit the body through a small opening in the abdomen.

Regardless of your age and condition, getting a routine medical check-up is always recommended. This is because some diseases present very generic or even no symptoms at all. Even as a doctor, the only way I can be sure of the diagnosis is through a detailed check-up and health screening.

I wrote this article because I understand that blood in urine can be very concerning. Do not worry too much! Oftentimes, the underlying cause of hematuria is treatable. That said, it is always better to be safe than sorry. As mentioned multiple times in the article, please visit a doctor if you see anything abnormal in your urine!

Get treatment quote for Hematuria

Dr Lincoln Tan is a urologist at Tan Urology, Gleneagles Medical Centre. He specializes in urologic cancer care and treatment. On top of his practice, he is also the chairman of the Singapore Cancer Society’s (SCS) Prostate Cancer Survivorship Advisory Panel.

Read more from Dr Lincoln Tan in his Q&A here. 


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1. Harvard Health Publishing. Hematuria - Harvard Health. Harvard Health. Published February 14, 2019. Accessed September 24, 2019.

2. Hubbard JG, Amin M. Pseudohematuria. Urology. 1977;10(3):190-192. doi:10.1016/0090-4295(77)90056-5

3. Sharp VJ, Barnes KT, Erickson BA. Assessment of Asymptomatic Microscopic Hematuria in Adults. American Family Physician. 2013;88(11):747-754. Accessed September 27, 2019.

4. Tan C, Chlebicki M. Urinary tract infections in adults. Singapore Medical Journal. 2016;57(09):485-490. doi:10.11622/smedj.2016153

5. Kidney Stones. Health Hub. Published 2019. Accessed September 26, 2019.

6. Bladder Cancer Symptoms. Johns Hopkins Medicine. Accessed September 26, 2019.

7. Benign prostatic hyperplasia (BPH) - Symptoms and causes. Mayo Clinic. Published 2019. Accessed September 26, 2019.

8. Ministry of Health Singapore. Clinical Practice Guideline – Glomerulonephritis. 2007 Mar;2.

9. Laryngakis NA, Caesar SR, Berns JS, Wein AJ. Runner’s Bladder: Exercise-Induced Hematuria With Lower Urinary Tract Pathology. UroToday Int J. 2011 Apr;4(2):art19.doi: 10.3834/uij.1944-5784.2011.04.01

10. Plumb RT: March Hemoglobinuria. The Journal of Urology. 1951 Apr;54(5):doi: 10.1016/S0022-5347(17)68533-1

11. Lotan Y, Choueiri TK. Patient education: Bladder cancer. UpToDate. Accessed September 27, 2019.

12. Shariat SF, Sfakianos JP, Droller MJ, Karakiewicz PI, Meryn S, Bochner BH. The effect of age and gender on bladder cancer: a critical review of the literature. BJU International. 2010;105(3):300-308. doi:10.1111/j.1464-410x.2009.09076.x

13. Lepor H. Managing and preventing acute urinary retention. Reviews in urology. 2005;7 Suppl 8(Suppl 8):S26-33. Accessed September 27, 2019.

14. Chow W-H, Dong LM, Devesa SS. Epidemiology and risk factors for kidney cancer. Nature Reviews Urology. 2010;7(5):245-257. doi:10.1038/nrurol.2010.46

842 views 4 Oct 2019 Medically reviewed by Dr Lincoln Tan on 5 Oct 2019.
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Disclaimer: Any answers provided are for general informational purposes only and is not a substitute for professional medical advice. If you think you may have a medical emergency, call your doctor immediately. Always seek the advice of your doctor before starting or changing treatment.

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Disclaimer: Any answers provided are for general informational purposes only and is not a substitute for professional medical advice. If you think you may have a medical emergency, call your doctor immediately. Always seek the advice of your doctor before starting or changing treatment.