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Going to have a colonoscopy. Passing blood in stool. Should i wait for the test?

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General Surgeon
Practicing since : 2008
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My father is going to have colonoscopy tomorrow for a suspected bleeding inside. The preparation of colonoscopy requires him to be on liquid diet and he has been given medicines for loose motion so that colon is cleared. The liquid stool that he is passing now is dark reddish in color.i asked the doctor if he is loosing blood through stool but he says since this color of stool is not fresh blood color,it may be old blood lying in the intestine and It takes few days for intestinal blood to get cleared even 4-5 days and i should not worry and doctor is ok if he carry on passing blood like this and wants me to wait till tomorrow morning when colonoscopy will be done.
My question is
1) is the theory that the blood is old and he is currently not bleeding fine?
2) if he carries on passing this dark reddish liquid stool,when should I start worrying?
3) is this type of old blood is normally seen and I shouldn't worry much?
4) Can you explain me more about the entire issue so that I have a better idea.
Mon, 17 Dec 2012 in Digestion and Bowels
Answered by Dr. Grzegorz Stanko 9 minutes later

Thank you for the query.

It is not reasonable to be sure that your father is not bleeding right now.
It is true that it takes 1-3 days for the old blood to be cleared but with regular motions. The idea of getting prepared for the colonoscopy is to get whole intestines cleared in one day (that is why he has this medicines). So if your dad has started clearing the intestine in the morning and there is still blood in the stool, for sure he is bleeding.
If it is about the color of the blood, we can say the higher is the source of the bleeding, the darker the blood is. So if the source is stomach, the blood will be black like a pitch, if the bleeding is from small intestine, the blood can be also black or dark, if the bleeding is from large intestine, the blood looks fresh and is usually mixed with stool, if the bleeding comes from hemorrhoids, the blood is red and on the surface of the stool.
I suggest you to take your dad to the ER and check his CBC. If the blood in stool used to be black before, colonoscopy can find nothing, and upper GI endoscopy might be necessary.

Hope this answers your questions. Feel free to ask further questions.
Above answer was peer-reviewed by
Follow-up: Going to have a colonoscopy. Passing blood in stool. Should i wait for the test? 1 hour later
He started his medications around 4pm and he had his first motion around 6pm. He till now had 5-6 motions but the last 2 motions were completely yellowish. Does it indicates that initial motions just released the old blood in the stool and now it is not bleeding.

Do I need to monitor regularly as I am assuming he will have these motions throughout night and if he has bled earlier ,he can start bleeding again?

Also does stool containing old blood confirms that he did bleed earlier and there is some issue in his intestine?

For your information,he did his endoscopy earlier and reports were normal .
Answered by Dr. Grzegorz Stanko 1 hour later

If the last 2 motions were yellowish, it means he probably has stopped bleeding and what was in the first motions it was the old blood.
Until you do not know the reason of bleeding, it is very hard to tell if and when it can start bleeding again. It is possible it will, and it is also same possible it wont.
Blood in stool is not a normal state. It always means that something inside the digestive system is bleeding. It can be simple hemorrhoid (most common), colon polyp, colon cancer, peptic ulcer, small intestine malformation.
In my opinion, your dad should have upper GI endoscopy performed before colonoscopy if the blood in stool is dark or black.

Hope this will help. Feel free to ask further questions.
Above answer was peer-reviewed by
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