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Bleeding and Clotting Disorders

Significance of abnormal blood color



My venous blood is extremely dark in color-- darker than any blood I`ve ever seen, and I`ve seen a lot of blood. CBC, H&H, and other routine blood tests appear normal. Are there any conditions associated with dark brown, almost black blood color?


While there is a rare condition that can cause the blood to look brown (methemoglobinemia), it is typically associated with the administration of one of several medicines that can cause this, and also makes the patient very symptomatic (short of breath). With all the tests normal, and I assume you having no symptoms, it is unlikely that there is a significant underlying condition that would lead to the blood looking this color.

I hope this helps out somewhat.

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Response by:

Spero R Cataland, MD Spero R Cataland, MD
Associate Professor of Clinical Internal Medicine
College of Medicine
The Ohio State University