Although finding blood in your urine can be a distressing discovery, it’s not always cause for concern. Whether visible to the naked eye or only under a microscope, blood in your urine (called hematuria) has a diverse range of causes and treatment options.
In this article, I’ll describe the two main types of hematuria, their symptoms and possible causes, and how hematuria can affect women, men, older adults, and children differently. I’ll also review how doctors diagnose and treat blood in urine.
In most cases, a visit to your doctor is recommended if you see blood in your urine, but the information outlined in this article will help you learn about the possible causes of your hematuria and common courses of treatment.
What Is Hematuria?
Hematuria describes the presence of blood in urine, which can affect men, women, and children.
The two main types of hematuria are:
- Gross hematuria: Also known as “visible hematuria,” gross hematuria refers to blood in urine that you can see without the aid of a microscope. In this case, urine can appear pink, red, or brown in color.
- Microscopic hematuria: This type of hematuria refers to trace amounts of blood in urine that are only detectable under a microscope. Microscopic hematuria is often asymptomatic and accounts for just 4-5% of clinical urology visits.
What Could Be Causing Blood in Your Urine?
There are many causes of hematuria, some of which can be specific to your gender and/or age. Though many of these conditions are not cause for concern, some may require medical attention.
The most common causes of hematuria are:
- Urinary tract infection: UTIs can cause both asymptomatic microscopic hematuria and gross hematuria. In fact, infections of the lower urinary tract, especially the bladder, are the most common causes of hematuria.
- Kidney or bladder stones: Stones are small, hard, and often calcified minerals that can form in your kidney or bladder over time. Though generally painless, stones can cause excruciating pain when creating a blockage or passing through your system. Bladder and kidney stones can cause both gross and microscopic hematuria.
- Kidney infection: Also known as “pyelonephritis,” kidney infections are bacterial infections that occur when an existing infection—like a UTI or bladder infection—spreads to the kidneys.
- Kidney disease: Microscopic hematuria is a common symptom of glomerulonephritis. This inflammatory disease that affects the kidneys’ filtering system. Glomerulonephritis can occur on its own or as a result of another disease, such as diabetes or lupus.
- Kidney injury or trauma: An injury to your kidneys, like that sustained from an accident or contact sport, can cause gross hematuria.
- Medication: Several drugs can cause hematuria, including blood thinners like heparin, warfarin (Coumadin), and acetylsalicylic acid (Aspirin). Antibiotics like penicillin and sulfa-containing drugs can also cause hematuria, as can the anti-cancer drug cyclophosphamide (Cytoxan).
- Intense exercise: Though strenuous workouts rarely cause gross hematuria, long-distance runners and other high-performing athletes can develop visible blood in urine after a particularly tough or intense workout.
- Inherited disorders: Sickle cell anemia (a red blood cell disorder) and Alport syndrome (a condition that affects kidney function) can cause gross and microscopic hematuria.
- Cancer: In rare cases, gross hematuria can be a symptom of advanced kidney, bladder, or prostate cancer.
The examples listed above are some of the most common causes of blood in urine, but there are additional causes that are specific to women, pregnant women, men, older adults, and children.
Possible causes of hematuria specific to women are:
- Vaginal bleeding: Many women see some vaginal blood in their urine while menstruating. However, if you notice blood in your urine outside of menses, or if you experience vaginal bleeding that’s not associated with your period, it could be a sign of something more significant.
- Endometriosis: Endometriosis is a condition that affects the endocrine system. It’s characterized by endometrial tissue that grows and sheds in locations outside of the uterus (think: the abdomen, ovaries, bladder, or intestines). Though symptoms can vary widely, hematuria that accompanies severe lower back pain may be a sign of endometriosis.
While microscopic hematuria or dipstick hematuria (when the oxidation of a urine test strip causes a color change) are very common in pregnancy, it’s important to follow up with your OB/GYN whenever you notice this.
If you have persistent or gross hematuria during pregnancy or postpartum, contact your doctor to see if there is another underlying cause, such as the kidney disease glomerulonephritis.
The causes of hematuria that affect men are:
- Enlarged prostate: Most common in older men, an enlarged prostate, also known as benign prostatic hyperplasia (BPH), can cause both gross and microscopic hematuria.
- Prostate infection: Due to the prostate’s proximity to the bladder and top of the urethra, an infection of the prostate (prostatitis) can cause similar symptoms to that of BPH, including blood in urine.
Hematuria is very common in older adults, and, in addition to the common causes listed above, can be caused by the following:
- Radiation cystitis: Radiation cystitis is a complication of radiation therapy in the treatment of multiple cancer types, including pelvic cancer. In addition to irritating the lining of the bladder and the urethra, it can cause hematuria.
- Clotting disorders: Gross hematuria is highly prevalent in older people with clotting disorders, like hemophilia. If you are older and have a clotting disorder, gross hematuria can be a significant risk factor for urologic disease, so it’s important to speak with your doctor about your symptoms.
Some of the common causes listed above, like UTIs and stones, can cause hematuria in children. In kids with hematuria, the condition will often resolve on its own, but it’s important to have it evaluated by the child’s primary care provider or pediatrician.
Otherwise, if blood in urine persists, it may indicate an inherited disorder or dysfunction of the kidneys. See your doctor or a nephrologist.
Diagnosing Blood in Urine
To diagnose hematuria, most doctors will begin with a urinalysis—a clinical sample and test of your urine to detect existing red blood cells. If hematuria is confirmed, your doctor may follow up with a physical examination and patient history to determine the cause.
Depending on your symptoms and the suspected cause, your doctor may perform additional testing to confirm the diagnosis:
- Urine culture: If your doctor suspects a kidney or bladder infection, they may collect your urine to send off for a culture. Urine cultures determine the presence of bacterial growth or red blood cells in the urine.
- Imaging tests: CT scans, MRIs, and ultrasounds help your doctor obtain images of your pelvis, blood vessels, and soft tissues to identify cysts, stones, tumors, or other masses that can cause hematuria.
- Cystoscopy: In this procedure, your doctor threads a narrow tube with a small camera into your bladder to determine whether there are signs of disease in the bladder or urethra.
- Blood tests: In some cases, your doctor may order a blood test to check for signs of a UTI, kidney failure, or other disorders.
Treatment Options for Blood in Urine
The treatment your doctor recommends depends on the cause of your hematuria.
Generally, exercise-induced hematuria does not require specialized treatment other than a change to your workout routine.
Similarly, medication-related hematuria will improve after you work with your doctor to stop taking the medication that caused the problem.
Alternative treatment plans vary depending on the identified cause:
- Kidney stones: Hematuria caused by kidney stones typically clear up once the stones are flushed through the urinary tract. If your stones are small, drinking lots of water can help to pass the stones. If the stones are larger, surgical procedures may be required.
- Kidney disease: Treatment for glomerulonephritis may include antibiotics, diuretics, and other medications. Additional dietary changes may be recommended to help reduce the work of your kidneys.
- Kidney injury or trauma: This treatment depends on the severity of the injury or trauma. In some cases, surgery may be required.
- Inherited disease: Treatment for an inherited disease varies by the type of disease. For sickle cell anemia, treatment may include medication, blood transfusion, or a bone-marrow transplant. Though there is no specific treatment for Alport syndrome, medications to control high blood pressure or ACE inhibitors may be prescribed.
- Cancer: Recommended treatment plans depend on the type of cancer and how far it has spread, as well as your age, health, and personal preferences.
When to See a Doctor
If you find blood in your urine, don’t panic. Blood in urine isn’t necessarily serious, but it’s still a good idea to check in with your doctor to determine the possible cause.
Did you know you can check your symptoms and get affordable treatment with the K Health app? Download K to check your symptoms using our AI-driven symptom checker and, if needed, text with a doctor in minutes. K Health’s board-certified, U.S.-based doctors can provide a treatment plan and prescription to resolve your symptoms as soon as possible.
Frequently Asked Questions
K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.