Noticing blood in stools can be alarming—and rightly so. While it might be due to something minor like hemorrhoids or a small tear in the anal lining, it can also be a symptom of more serious underlying conditions such as colorectal cancer, inflammatory bowel disease (IBD), or gastrointestinal infections.
The appearance of the blood—whether bright red, dark maroon, or black—can give clues about its source. For example, bright red blood in the stool usually comes from the lower gastrointestinal tract, such as the rectum or colon, while darker blood might indicate bleeding higher up in the digestive system.
Regardless of the cause, seeing blood in stools is a sign that diagnostic evaluation is necessary. Timely investigation can help identify the root cause and guide appropriate treatment.
Initial Assessment: Medical History and Physical Exam
When you report blood in stools to your doctor, the first step is a detailed medical history. Your physician will ask about the duration and appearance of the bleeding, any accompanying symptoms like weight loss or abdominal pain, changes in bowel habits, and family history of gastrointestinal disorders or cancer.
A physical examination may follow, including a digital rectal exam to check for hemorrhoids, fissures, or masses. If necessary, your doctor may also test a stool sample for hidden (occult) blood and other abnormalities like infection or inflammation.
These basic steps are essential in determining whether further investigation is needed and which diagnostic tests are most appropriate.
Colonoscopy: The Gold Standard
One of the most commonly recommended diagnostic tools after finding blood in stools is a colonoscopy. This procedure involves inserting a flexible tube with a camera into the rectum to inspect the entire colon and rectum. It is often done under sedation and allows for both diagnosis and treatment, such as removing polyps or taking tissue samples (biopsies) if needed.
A colonoscopy is especially important for individuals over the age of 50 or those with a family history of colorectal cancer, as it can detect cancer at an early, treatable stage or even prevent it by identifying precancerous growths.
Flexible Sigmoidoscopy: A Less Extensive Alternative
A flexible sigmoidoscopy is similar to a colonoscopy but only examines the lower part of the colon (sigmoid colon and rectum). While it doesn’t provide a complete view of the large intestine, it may be suitable for patients with low-risk factors and rectal bleeding.
This test can also detect tumors, inflammation, or hemorrhoids. If abnormalities are found, a full colonoscopy might still be needed for further evaluation.
CT Colonography (Virtual Colonoscopy)
For patients who cannot undergo traditional colonoscopy due to medical or personal reasons, a CT colonography is a non-invasive alternative. It uses CT scanning to produce detailed images of the colon and rectum.
Although this test is highly effective in detecting large polyps and cancers, it cannot remove polyps or take biopsies during the procedure. If abnormalities are detected, a standard colonoscopy will still be required for follow-up.
Upper Endoscopy for Upper GI Tract Bleeding
If your doctor suspects that the bleeding originates higher in the digestive tract—especially if the stools are black and tarry rather than bright red—they may recommend an upper endoscopy.
This involves passing a thin, flexible tube through the mouth to examine the esophagus, stomach, and upper part of the small intestine. Conditions such as stomach ulcers, esophagitis, or gastritis can be identified and treated during the procedure.
Imaging Tests and Lab Work
Additional imaging tests such as an abdominal ultrasound, CT scan, or MRI might be ordered if tumors or vascular abnormalities are suspected. These tests provide a more detailed look at organs and tissues that cannot be reached via endoscopy.
Blood tests may also be performed to check for anemia, infections, or signs of inflammation. If blood loss has been occurring over a long period, your hemoglobin levels might be low, indicating chronic bleeding.
When to Seek Immediate Care
While not every instance of blood in stools indicates a medical emergency, certain symptoms should prompt urgent attention. These include heavy or continuous bleeding, dizziness or fainting, severe abdominal pain, or a rapid heart rate. These signs could indicate significant blood loss or a serious underlying issue.
It’s always better to err on the side of caution when gastrointestinal bleeding is involved. Prompt evaluation ensures the best outcomes and can prevent complications.
Conclusion
Finding blood in your stool can be unsettling, but it’s also a valuable warning sign that shouldn’t be ignored. From colonoscopy to imaging tests, a variety of diagnostic tools are available to uncover the cause and guide treatment. Whether the issue is minor or serious, early detection through appropriate testing can make all the difference in protecting your long-term health.
