Risk of Fecal occult blood (FOB)
由於早期的大腸癌徵狀包括大腸出現腫瘤或瘜肉，並有出血的情況，導致大便帶血，俗稱「 血便」。因此大家可以透過「大便隱血測試」，以試管收集少量的大便樣本，再送到化驗中心檢驗大便樣本中是否有肉眼看不見的血液。大便隱血檢查是一個初步篩查大腸癌的方法，此檢查為非侵入式，亦較為方便及安全。現時香港衞生署推出的<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.
Blood in the stool can appear without any visible colour change or without any fresh blood in the stool. When the polyps in the intestinal wall bleed, the stool may contain hidden blood in the faeces (occult blood). Patients who have doubts can conduct a FOBT or a colonoscopy in accordance with the medical 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.
