Diagnostic measures for blood in stool
As with all diseases, the diagnosis begins with a detailed patient consultation. In this discussion, the doctor will focus on the type of blood, the consistency and frequency of the stool and accompanying complaints such as abdominal pain or vomiting. This is followed by a physical examination, including a palpation of the abdomen and a rectal examination, which the doctor performs with a finger.
The rectal examination makes it easy to detect haemorrhoids and tears in the mucous membrane of the anus. In some cases, tumours located in the rectum can also be palpated. If the physician has not yet been able to find the cause, a blood test is performed, which is mainly performed to detect anemia.
If an anaemia is present, this indicates that the bleeding is already a long or chronic process. Sometimes, for example, a stomach ulcer is only diagnosed by a routine blood test or a blood test based on another indication by abnormal blood values, in the sense of an anaemia. If the symptoms indicate a gastrointestinal infection, a stool test is performed in addition to a blood test to determine the triggering pathogen.
In many cases, blood in the stool also requires an endoscopy of the gastrointestinal tract. For this purpose, a gastroscopy (gastroscopy) or a colonoscopy (colonoscopy) may be considered. The gastrointestinal tract can be examined with a camera tube system.
The system is inserted either by mouth (gastroscopy) or rectally (colonoscopy). If it is fresh blood in the stool, the doctor will always choose a colonoscopy, as the cause is located in lower parts of the intestine. If tarry stools are present, a gastroscopy is usually performed because the cause is suspected further up.
A gastroscopy or colonoscopy is usually performed as an outpatient procedure. The examination takes about 15 to 30 minutes. Rarely an X-ray examination is also performed for clarification.
The most important test for detecting blood in the stool is the so-called “haemoccult test”. This is an easy to perform test that is available from every doctor and in pharmacies. It plays an important role in the prevention and diagnosis of intestinal cancer.
The Hemoccult test is very inexpensive and easy to use, which is why it is recommended annually for colorectal cancer screening from the age of 50 and is covered by health insurance companies. The stool is filled into a test tube and then examined in the laboratory for a specific molecule of human blood. This enables it to detect with a high degree of certainty even the smallest invisible traces of blood in the stool.
This test is used almost exclusively in today’s practice. Occasionally, the so-called “guaiac test” is still used, which causes a colour reaction on contact with blood, but gives significantly less reliable results than the haemoccult test. The disadvantage of all test procedures for blood in stool is that in many diseases there is no bleeding in the intestine at the time of testing or that false-positive results are obtained due to the consumption of bloody meat or other impurities in the intestine. The tests only prove the symptom of blood in the stool, but do not provide any indication of the cause or the underlying disease.
