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Blood in the Urine

Blood in the Urine

The presence of blood in the urine or hematuria can be frightening. Frequently, it is not life-threatening. For some people, even an intense exercise session may cause hematuria. However, they should not ignore this symptom, as it could indicate serious health conditions that only health professionals should assess.

“Hematuria is a term put together from the Greek words haima (blood) and ouron (urine) to refer to the presence of blood in the urine. The blood may be visible to the naked eye (macrohematuria, gross or frank hematuria) or only under the microscope (microhematuria). In some patient groups it is a frequent finding. The reported prevalence of asymptomatic microhematuria (aMH) ranges between 1.7% and 31.1%; in routine clinical practice, a prevalence of 4% to 5% appears realistic”1

Diagnosis and Incidence of Hematuria 

“Hematuria is a prominent symptom in diseases of the genitourinary tract, and, moreover, it is often the only symptom of which the patient complains in the early stages. In such cases the first duty of the surgeon is to apply all the means at his disposal for discovering from which portion of that tract the blood is issuing.”2

The presence of blood in the urine usually changes the color of water in a toilet bowl. When it is invisible to the naked eye (microscopic hematuria), the patient requires screening sessions or urinalysis for effective diagnosis.

“Hematuria may be recognized by the patient; so-called ‘frank’, ‘visible’, or ‘macroscopic’ hematuria. Alternatively, it may be detected only on examination of urine, most commonly as a positive urinalysis test for blood (chemical dipstick), or as more than a set number of red cells per high-power field on microscopy, or in a Coulter counter. Under these circumstances, it is called ‘non-visible’, ‘invisible’, or ‘microscopic’ hematuria. Isolated non-visible hematuria is defined as three or more red blood cells per high-power field in the absence of infection or proteinuria. What is considered ‘normal’ varies greatly as healthy people lose around a million red blood cells in their urine daily, equating to around one cell per high-power field. Chemical dipsticks give a ‘negative’ finding with this level of hematuria.”3

The incidence of hematuria may vary depending on age. “Hematuria is common, seen in 2% to 30% of the adult population. Older patients and smokers have higher rates of hematuria. Smokers are also at an increased risk of genitourinary cancer.”4

Hematuria Sources

  1. Upper urinary tract: problems related to the kidneys.
  1. Lower urinary tract: problems associated with the ureters, the bladder and or the urethra.

UTI-related Symptoms of Hematuria

  • Weight loss for unknown reasons (mostly in chronic infections).
  • Pain or burning feeling when urinating.
  • Frequent and sometimes low urine output.
  • Elevated body temperature, chills, rigor, abdominal pain, ache in the sides and back.
  • Difficulty in passing urine or urine initiation.
  • Blood clots in urine.
  • Painful sexual relations.
  • Heavy menstrual bleeding (menorrhagia).
  • Urine leaks or occasional dribbling.
  • Frequent nocturnal urination or nocturia.

Urinary Tract-related Causes of Hematuria

 “When passing blood in urine is associated with pain, especially abdominal pain, it could be associated with kidney or ureteral stones. The pain could be localized to the back, to the side, to the groin, or the penis in men and the labia in women. If you are passing different-shaped clots in your stream, they could represent bleeding from the urethra or prostate (in men). Clots can be wormlike, and if associated with pain it could represent clots coming from your ureters (tubes from your kidneys to your bladder).”5 The specific causes of Hematuria related to the urinary tract are:

  • Renal stones.
  • Urinary tract infections.
  • Cystitis (infection or inflammation of the bladder).
  • Inflammatory conditions of the urethra.
  • Inflammatory conditions and kidney infections (glomerulonephritis).
  • Cancerous conditions of the kidneys, the bladder and/or the prostate.
  • Trauma to the urinary tract.
  • Surgical or other medical-related procedures of the urinary tract, including catheterization and circumcision.
  • Polycystic disease of the kidneys.
  • Prostate hypertrophy.
  • Kidney failure (end-stage and acute).
  • Glomerulonephritis following streptococcal infections in children.
  • Medications such as rifampicin, aspirin, warfarin, quinine and phenytoin sodium.

Blood disorders that can lead to hematuria

  • Blood clotting disorders such as hemophilia.
  • Sickle cell disease.
  • Kidney thrombi.
  • Low platelet count.
  • Leukemia (blood cancer)

“Hematuria can be confused with other urine discoloration caused by something other than blood in the urinary tract, such as foods like beets, bleeding from menstruation, blood from the gastrointestinal system, or medications.”6

What to do when Hematuria is discovered

Check with a doctor immediately. Hematuria is usually painless with no other symptoms. Specialists must perform a thorough investigation to determine early diagnosis and treatment. If the patient has a urinary tract infection, avoid bladder irritants such as tea, coffee, cola drinks, and citrus fruit juices.

“The treatment for hematuria varies and is dependent upon the cause. Your doctor will focus treatment on the condition or disease causing the blood in your urine. If stones are determined to be the cause of hematuria, treatment may require surgery. If your doctor suspects a tumor in the urinary tract or prostate gland based on the imaging, a biopsy may be recommended and possible treatments may include chemotherapy, surgery or radiation therapy.”7

Confirming the causes of Hematuria

After diagnosing the presence of blood in the urine, confirming the causes of hematuria requires certain tests. “The health care provider will take a thorough medical history. If the history suggests a cause that does not require treatment, the urine should be tested again after 48 hours for the presence of RBCs. If two of three urine samples show too many RBCs when viewed with a microscope, more serious causes should be explored.”8

The health professional may prescribe one or various tests to establish the root cause(s):

  • Urine analysis, including culture and sensitivity tests.
  • Blood tests.
  • Imaging investigations such as IVP (intravenous pyelogram), X-ray, CT (computerized tomography) and even MRI (magnetic resonance imaging), and kidney imaging tests.
  • Cystoscopy.
  • A biopsy.
  • Additional research targeting surrounding tissues to exclude other underlying health disorders.

“Macrohematuria always requires investigation. The hematuria may be visible from a concentration as low as 1 mL blood per liter of urine. The color and the intensity of the color correlate with the amount of blood content: fresh arterial blood (bright red, ranging from pink to ketchup-colored) can be distinguished from venous blood (dark red, Bordeaux red) and from old blood (dark brown or black). Rarely, urine may be colored red or dark owing to myoglobinuria (due to rhabdomyolysis) or hemoglobinuria (due to hemolysis). A diagnosis of hematuria is confirmed by demonstration of red blood cells in the urinary sediment as shown by qualitative and quantitative microscopy. In microhematuria, there is a microscopic increase in red blood cell content above the physiological threshold. The threshold is given as either ≥ or >3 red blood cells per high-power field in microscopic assessment of the urinary sediment in two out of three correctly collected urine samples. Some medical specialty societies regard evidence from one dipstick as adequate, while others require more than just one (e.g., positive results on two out of three dipsticks) for a diagnosis of “significant” microhematuria.”9

Final Thoughts

“Hematuria is a common clinical finding and represents the most frequent presenting symptom/sign of urothelial carcinoma of the bladder, particularly among persons 40 years and older. Proper evaluation of hematuria is necessary to identify the one person in ten who may have a life-threatening malignancy or other treatable condition. The American Urological Association (AUA) Best Practice Guidelines recommend that all patients 35 years and older, presenting with asymptomatic hematuria (>3 red blood cells per high-power field), for which benign causes have been ruled out, undergo cystoscopy. Additionally, these guidelines recommend evaluation of the renal parenchyma and urothelium, with CT urography (CTU) being the preferred imaging modality.”10

Regular medical consultations are essential to prevent blood in the urine. “Hematuria can be caused by a variety of conditions including stones, infection, a tumor, or injury involving the kidneys, urinary tract, prostate gland and/or genitals. It could also be caused by a bleeding disorder or by taking certain medications.”11

Other reasons are unrelated to a disease, or unavoidable. “Many causes of blood in the urine are not necessarily preventable, such as urinary tract infection or cancer, enlargement of the prostate, blood diseases, and kidney diseases. Other causes, like strenuous exercise and the use of certain medications, can be preventable to some extent. Maintaining adequate hydration can be helpful in reducing the chance of developing kidney stones.”12

The treatment of hematuria consists in the management of the primary cause. Patients do not require treatment if the bleeding is unconnected to a serious condition. As for UTI-related hematuria, the doctor will prescribe antibiotics. After six weeks of antibiotic treatment, perform another urinalysis to confirm it was effective. 



(1, 9) The Investigation of Hematuria. Bolenz, C., Schröppel, B., Eisenhardt, A., Schmitz- Dräger, B., & Grimm, M. Deutsches Ärzteblatt International. 2018.

(2) Surgery: Some Causes of Hematuria. The Hospital: Biomedical Journal Digitization. 1909.

(3) Non-visible versus visible hematuria and bladder cancer risk: a study of electronic records in primary care. Price, S., Shephard, E., Stapley, S., Barraclough, K., & Hamilton, W. British Journal of General Practice. 2014.

(4, 6) Blood in the Urine (Hematuria). Matulewicz, R., & Meeks, J. Journal of American Medical Association. 2016.

(5) Hematuria: Blood in the urine. University of Iowa Hospitals & Clinics. University of Iowa Health Care. 2017.

(7, 11) Hematuria or Blood in Urine.  Radiological Society of North America. For Patients. 2018.

(8) Hematuria: Blood in the Urine. The National Kidney and Urologic Diseases Information Clearinghouse. 2012.

(10) Variation in the intensity of hematuria evaluation: a target for primary care quality improvement. Friedlander, D., Resnick, M., You, C., Bassett, J., Yarlagadda, V., Penson, D., & Barocas, D. The American Journal of Medicine. 2014.

(12) Blood in the urine reasons. Stöppler, M. eMedicineHealth. 2018.


María Laura Márquez
13 October, 2018

Written by

María Laura Márquez, general doctor graduated from The University of Oriente in 2018, Venezuela. My interests in the world of medicine and science, are focused on surgery and its breakthroughs. Nowadays I practice my more:

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