Risk of Fecal occult blood (FOB)
The early symptoms of colorectal cancer include tumours or polyps in the colon and usually associates with blood in the stool. Therefore, a Faecal Occult Blood Test (FOBT) can be conducted to see if there is any blood in the stool by collecting stool specimens in tubes and sending them to the laboratory. The test is a preliminary method to screen for colorectal cancer and it is a non-invasive test that is safer and more convenient. Colorectal Cancer Screening Programme launched by the Department of Health utilises the FOBT to find people who are at risk of having colorectal cancer and provide a colonoscopy for those who have blood in the stool. Contact us for more information about the Colorectal Cancer Screening Programme and the Faecal Occult Blood Test.
It is common to have gastrointestinal (GI) infections but it is important to pay more attention to the form and colour of the stool. If the stool is dark brown or black in colour or with flesh blood, it is recommended to receive further examinations as soon as possible. However, the blood in stool is just a symptom of colorectal cancer. It can be due to a number of other conditions, such as colon polyps, anal fissure, piles, ulcer in the lower GI tract etc. It is recommended to seek medical assistance and conduct tests to investigate the cause of the bleeding.
Judgment of bloody stool
Bloody stool does not necessarily mean a change in color or accompanied by blood visible to the naked eye. When a polyp in the intestinal lining begins to bleed, there may be invisible blood in the stool (also called occult blood). In fact, bloody stools are very common. Regardless of age or gender, bloody stools may occur.
The pattern and color of bloody stools
Bloody stool means that the stool contains blood, and the blood usually bleeds from the digestive tract to the anus, and then mixes with the stool. The color of bloody stools will generally appear bright red, dark red, or black depending on the location of the bleeding.
What does bright red bloody stool mean?
Bright red bloody stool generally refers to lower gastrointestinal bleeding, hemorrhoids near the anus (including external hemorrhoids/internal hemorrhoids), or anal fissures, resulting in bloody stools.
What does dark red or black bloody stool mean?
If the stool is dark red or black, it generally refers to bleeding in the upper gastrointestinal tract, tumors or polyps in the large intestine.
Does it hurt when you have bloody stools?
The presence of blood in the stool does not necessarily cause pain to the patient. If the blood in the stool is due to polyp bleeding in the upper or lower gastrointestinal tract, or bleeding from the gastrointestinal lining, the patient may not feel pain. If a patient experiences anal pain during defecation and bloody stool, it is possible that the pain is caused by hemorrhoids or anal fissure..
Patients with doubts can undergo fecal occult blood testing, colonoscopy, or related examinations based on their doctor's advice.
Procedure to collect specimens for the FOBT
It is a simple procedure to collect specimens for the FOBT and it can be done at home on your own. The followings are the steps for specimen collection:
Step 1: Place a holder for collecting the stool in the toilet bowl, then open your bowels
Step 2: Twist lid off the FOBT tube and scratch sampling probe across stool surface in all directions
Step 3: Insert the sampling probe back into the FOBT tube, screw the lid tightly and handle the tube with care
Step 4: Seal the FOBT tube into the small plastic bag and return it to a designated specimen collection point
Precautions of FOBT
It is recommended to prepare a holder, such as a plastic bag, for collecting the stool in the toilet bowl, to avoid the specimens from contacting with urine or toilet water and interrupt the test results. Returned the specimen to a specimen collection point within 4 days of collection. As the FOBT is to see if there is blood in the stool, it is also recommended to avoid collecting specimens on the day when the pile bleeds to avoid contamination of the sample.
FOBT Result
A negative FOBT result means that no blood is detected in your stool. It is recommended to pay more attention to the bowel habits, the forms and colours of the stool. If the following symptoms of colorectal cancer or any other suspicious conditions are found, it is recommended to seek medical assistance as soon as possible.
．Blood in the stool
．Anaemia
．Change of bowel habits (including constipation and diarrhoea)
．Persistent diarrhoea
．Unexplained belly pain
．Polyps, abnormal cells
FAQ for FOBT
1. 1. How do I take a FOBT?
You can take a free FOBT to see if there is blood in your stool, if you are eligible to join the Colorectal Cancer Screening Programme subsidised by the Department of Health. For those who do not fulfil the criteria for the programme, it is recommended to make enquiries to medical institutions for relevant tests and the fees.
2.The result of my FOBT screening is positive, do I have colorectal cancer?
A positive FOBT result means that blood is detected in your stool. This can be due to a number of other conditions apart from colorectal cancer, such as ulcer or bleeding polyp in your colon. You should discuss with your doctor regarding further investigations to look for the cause of the bleeding.
3. Can I take a FOBT if I have blood in my stool?
It is not recommended to take a FOBT if you have blood in your stool, and you should seek medical assistance immediately. Seek medical assistance and conduct further investigations if you have doubts.
4. Is FOBT accurate?
FOBT is an initial screening for colorectal cancer to see if there is bleeding in the colon. You may consider conducting a colonoscopy for a more accurate result regarding the health of your colon and the condition of the colon polyps. If there are any polyp or suspicious conditions found during the colonoscopy exam, the polyp removal procedure and biopsy can be carried out right away.
