Blood in Urine: Key Facts, Functions, and Health Risks

What Is Blood in Urine (Hematuria)?

Blood in urine, also called hematuria, is a sign that there may be a problem. This can be a visible sign or detected only under a microscope.

The function of hematuria as a biomarker lies in its role as an indicator of possible issues within the urinary or urogenital system. When blood is found in the urine, it can signal inflammation, infection, injury, or other underlying health conditions, prompting further medical investigation.

Hematuria often acts as an early warning system, helping healthcare providers detect potential problems before they become serious. It’s one of the biomarkers that can point to disorders affecting the kidneys, bladder, urethra, or other related structures.

When Is Blood in Urine Testing Recommended?

Testing for blood in the urine is commonly done as part of routine health checkups or when specific symptoms or risks are present. The test is prescribed to help diagnose or rule out certain conditions. Below are the key situations where a healthcare provider might recommend a hematuria test:

• Annual Health Checkup: As part of routine urinalysis during yearly exams.
• Persistent Urinary Symptoms: Testing is recommended if you experience pain during urination, frequent urges, or blood in the urine.
• Unexplained Lower Back or Abdominal Pain: Pain near the kidneys or bladder area might prompt testing.
• Injury: After an accident or injury impacting the back, abdomen, or pelvic area.
• Kidney-Related Symptoms: Swelling in the lower body, high blood pressure, or protein in the urine may warrant a test.
• Known Risk Factors: If you have a history of kidney stones, infections, or high-risk occupations for urinary tract issues.

How Is Blood in Urine Testing Conducted?

Blood in urine testing is done through a urinalysis, which can detect both visible and microscopic traces of blood. Occult blood in urine, which is not visible to the eye, is often identified only through these types of laboratory tests.

There are two main ways blood in urine, including occult blood, is identified:

1. Visual Examination: Gross hematuria, where blood is visibly present in the urine, changes the color to pink, red, or brown.
2. Microscopic Examination: Even if urine appears normal to the eye, a laboratory examination can detect red blood cells under a microscope.

Hematuria testing is typically part of a standard urinalysis. This test is often included in:

• Routine Physical Exams: General checkups or wellness exams.
• Kidney Function Panels: Comprehensive testing that checks for various kidney-related biomarkers.
• Post-Injury Examinations: Particularly if the injury affects the urinary or kidney area.

Preparations

Before a hematuria test, certain steps can improve accuracy:

• Avoid Certain Foods and Drinks: Some foods, like beets, rhubarb, or berries, can color the urine and affect test results.
• Limit Physical Activity: Avoid heavy exercise before the test, as it can influence the results.
• Medications: Inform your doctor about any medications you’re taking that might impact the test outcomes.

What Do the Results Mean?

The normal result for blood in urine is “not detected.” Ideally, no blood cells should be present in urine, and this is what is considered healthy in standard medical exams. However, trace amounts are sometimes found, especially in women during menstruation. 

Some labs may use different terms like "positive/negative", "present/absent" and so on but the interpretation remains the same.

What Does Detection of Blood in Urine Mean?

Detecting blood in the urine can indicate a range of health concerns. Here are some common causes:

• Urinary Tract Infection (UTI): An infection in the bladder or urinary tract can cause bleeding.
• Kidney Stones: Stones moving through the urinary tract may damage tissue, leading to blood in the urine.
• Prostate Issues: In men, prostate infections or enlargement can result in hematuria.
• Bladder or Kidney Tumors: While rare, tumors in the urinary system can cause blood in the urine.
• Kidney Injury: Physical trauma to the kidneys can lead to bleeding.
• Urethritis: Inflammation of the urethra can cause bleeding and discomfort during urination.
• Renal Vein Thrombosis: A clot in the kidney vein may lead to bleeding.
• Ulcerative Cystitis: Chronic inflammation of the bladder lining, often due to infection or irritation, can result in hematuria.

If hematuria is detected, there are steps you can take to manage or prevent worsening symptoms. Here are some practical recommendations:

• Increase Fluid Intake: Drinking water helps flush out the urinary tract, potentially reducing infection risk.
• Practice Good Hygiene: For those prone to UTIs, maintaining hygiene can prevent infections that lead to hematuria.
• Avoid Certain Foods: Foods with high oxalate content, like spinach or nuts, can contribute to kidney stones in susceptible individuals.
• Limit Salt and Protein Intake: High salt or excessive protein in the diet can increase the risk of kidney stones and other issues.
• Quit Smoking: Smoking increases the risk of bladder and kidney cancer, which can cause blood in the urine.
• Regular Medical Checkups: Routine exams help catch issues early, preventing minor problems from becoming major concerns.

Which Specialist Should You Consult?

If blood in the urine is detected, it’s essential to consult a urologist. A urologist specializes in diagnosing and treating issues related to the urinary tract. In some cases, a nephrologist (a kidney specialist) might be consulted if the problem is likely linked to kidney function.