Finding blood in your urine can be alarming—but what if you can’t see it at all?

That’s the case with microscopic hematuria, a condition in which red blood cells are present in your urine but are only detectable under a microscope or through a urinalysis. While it might seem like a harmless fluke—especially if you feel fine—it can sometimes be an early sign of a more serious urologic issue.

If you’ve been told you have microscopic hematuria, it’s important not to brush it off. Here’s what you need to know—and why a visit to a urologist could be the next best step.

What Is Microscopic Hematuria?

Hematuria refers to the presence of blood in the urine. It comes in two main forms:

• Gross hematuria – Blood is visible to the naked eye (your urine may look pink, red, or cola-colored).
  
• Microscopic hematuria – Blood is not visible, but detected via a routine urine test.
  

Often, microscopic hematuria is discovered incidentally during an annual physical, employment screening, or preoperative workup.

In many cases, it’s benign and self-limited—but it can also signal an underlying condition, particularly in older adults or those with certain risk factors.

Causes of Microscopic Hematuria

There are numerous reasons why microscopic blood might appear in the urine. Some are harmless, while others require further evaluation.

Benign Causes:

• Vigorous exercise
  
• Sexual activity
  
• Recent trauma or injury
  
• Menstruation (in females)
  
• Dehydration
  

Urologic or Medical Causes:

• Urinary tract infection (UTI)
  
• Kidney stones
  
• Enlarged prostate (BPH)
  
• Bladder or kidney cancer
  
• Glomerular disease (kidney inflammation)
  
• Polycystic kidney disease
  
• Trauma to the urinary tract
  
• Certain medications (like blood thinners)
  

Determining whether the blood is coming from the kidneys, the ureters, the bladder, or the urethra is key to proper diagnosis.

Who Needs to Be Evaluated?

Not everyone with microscopic hematuria needs an extensive workup. But certain patients should be referred to a urologist, including:

• Adults over 35 years old
  
• Smokers or those with a history of tobacco use
  
• People with a family history of urinary tract cancers
  
• Individuals with frequent UTIs, kidney stones, or urinary symptoms
  
• Patients with persistent hematuria on repeat testing
  
• Anyone with gross hematuria, even once
  

The American Urological Association (AUA) recommends a complete urologic evaluation for high-risk patients—especially since some bladder or kidney cancers may present only with microscopic hematuria in their early stages.

What Happens During a Urologic Evaluation?

A urologist will typically perform a thorough evaluation to rule out serious conditions and identify treatable causes.

Key components may include:

• Repeat urinalysis and urine culture – To confirm persistent hematuria and rule out infection
  
• Urine cytology – A test that looks for abnormal or cancerous cells in the urine
  
• Blood tests – To evaluate kidney function and look for signs of systemic disease
  
• Imaging tests – Most commonly a CT urogram (which looks at the kidneys, ureters, and bladder in detail)
  
• Cystoscopy – A minimally invasive procedure that uses a small camera to inspect the inside of the bladder and urethra
  

For some patients, especially younger ones with no risk factors and only a single abnormal test, a watch-and-wait approach may be appropriate. But for those in higher-risk categories, prompt investigation is essential.

What If All Tests Are Normal?

In many cases, no definitive cause is found—even after a complete evaluation. This is called idiopathic hematuria, and it’s relatively common.

If all serious conditions have been ruled out and you have no other symptoms, your urologist may simply recommend:

• Annual monitoring
  
• Repeat urine testing
  
• Lifestyle modifications (such as hydration, limiting certain medications, or managing blood pressure)
  

Even without a clear diagnosis, follow-up is still important to ensure the condition doesn’t change over time.

Microscopic Hematuria in Women vs. Men

Women are often more prone to UTIs, which can cause transient microscopic hematuria. Men, especially over 50, may experience hematuria related to prostate issues. That’s why evaluation is tailored to your age, sex, history, and risk factors.

Never assume that it’s “just a UTI” or a one-time fluke—particularly if you’re not experiencing classic infection symptoms like burning or urgency.

Final Thoughts

Microscopic hematuria is easy to ignore—after all, you can’t see it, and it often causes no symptoms. But for some people, it may be the first and only sign of a more serious condition, such as kidney disease or cancer.

That’s why urologists take even microscopic findings seriously, especially in adults over 35 or anyone with risk factors. A comprehensive evaluation may offer peace of mind—or allow for early detection and treatment when it matters most.

If you’ve been told your urine test shows blood—don’t wait. Talk to a urologist and get the answers you deserve. We recommend urologist brooklyn.