What determines whether blood is bright red or a dull brick-red?
821922
it depends how much blood you have, if there's a lot, then it will appear a brick red color, but if its not so much, then it looks bright red untill it dries, then its brick red once again
941553
Have the dr. check your red blood cells and H&H you might be anemic.
1126412
I have heard that light red blood isn't so bad, but that dark red could be a problem.  Either way I would talk to your doctor for sure, to be on the safe side.
589426
No, in general menstrual blood color can vary from bright red to an almost black color. This is normal. You will usually find that your periods will start a lighter color (more reddish) and then turn brown or black for the remainder of your periods. However, if your whole period is a brown or black color I would go to a doctor just to check it out.
205421
only one true way to know and that is a blood test where the amount of hemoglobin and number of red blood cells are counted per ml of blood (hematocrit), classically referred to as an "H & H".  Gerenal sympoms of fatigue, pallor, rapid heartbeat, feeling short of breath may all be signs of anemia or many other things and you will not be able to differentiate this on your own.  Anemia must have a cause (chronic blood loss, acute blood loss, iron defficiency, vitamin B12 defficience, acute viral illness (some types) just to name a few).  Get seen by a doc, get an exam and a blood test to find out.
252838
human hemoglobin contains one atom of iron in its core. This iron plus oxygen turns red; plus carbon dioxide turn dark red; plus carbon monoxide turns very bright red. So, the color of blood comes from the iron in the hemoglobin molecule AND the compound binding to it. By the way, some crab species have copper in their hemoglobin instead of iron, so their blood is... BLUE!
123094
Bright red or dark red?  It depends.  Bright would indicate that you have some sort of cut or tear close to the "exit" point.  Dark may indicate that you have intestinal bleeding or other problem in the digestive system.  Don't leave it to guessing, get your doctor's opinion if you're having problems with bloody stool.
1050848
"Frank" blood means it is bright red, which means it is coming from a bleeding wound...an active stomach ulcer, for instance. \n\nThis term differentiates it from old/dark blood which means it has been outside the vein/artery for awhile.
236057
Depends on what grade you're in. You need something red, and some way of showing the path the blood is taking. Perhaps you should make a big cardboard or foam human body, and tape red strings all across the body in a realistic model of the human circulatory system.
957851
Yes.  Hematocrit represents the percentage of the blood volume that is composed of blood cells.  Mathematically, it is:\n\nHct = RBC x MCV\n\n(Hct = hematocrit, RBC = red blood cell count, MCV = mean corpuscular volume)\n\nIf your blood cells are really small (low MCV), then the hematocrit can be low even if you have the appropriate number of cells.\n\nCommon causes of microcytic anemia are iron deficiency, thalassemia, sideroblastic anemia, and lead poisoning.  In addition, various chronic disease processes can result in a microcytic anemia.
156204
I don't believe that guy called her a moron for giving the right answer. Yes blood without oxygen is blue but it may appear green due to you looking at it through your skin. I'm sure you've seen someone with blue lines on their body. When blood becomes oxygenated...the Fe is pulled to the center of the heme ring. It's actually this conformational change that produces the red color. Not rust. Also to comment. The Fe is contained within the porphyrin ring but not in a flat structure. It is partially off center and is pulled more equally within the ring structure with the addition of oxygen. If you looked it up you'd know I wasn't making **** up. Although i do apologize for the blue comment. But we see blue because of the absorption of light at the surface of our skin. At least while the blood is stil in circulation. You need to be less critical. Yes all of them are red but to the naked eye under the skin they clearly appear blue. It's not total "bullocks" for someone to assume such. The intelligent should learn to be teachers not arrogant tactless shrews.
578703
hemorrhoids deeper inside the rectum don't hurt as much as ones on the outside. \n\nbright red blood can also be a sign of colon or rectal cancer. if you are over 50 or have a family history of colon cancer, you need to go to the doctor and have a colonoscopy ASAP.
587615
oxygenated blood is red. deoxygenate blood is blue, you always bleed red because blood pulls the oxygen out of the air the same way  it would in your lungs, and yes it happens to everyone
1112199
Only a blood test will tell...
628386
Yes.  Sometimes the blood isn't very red at the beginning and the end.  Expect it to be weird before it gets regular- just keep supplies with you just in case and keep track of it.
612119
blood is red...not black
1026400
You are probably anemic or low in red blood count. You should see a doctor for medical opinion. Do not take any medications before asking or seeing your doctor first.