Sounds like he may have worms
Probably a severe parasitic infection of some sort. You need to take him to a vet as soon as possible.
No, blood plasma would be the watery part of blood.
A dog's "poop" is usually called, stool. Example, if your dog has blood in its poop you would say, "there is blood in my dog's stool."
plasma is the consistence of a watery pudding
Worms
If the stool has blood in it, also could be due to red food dye from drinks like punch or gatorade.
Mostly stool samples are tested for bacteria and blood. To test stool for drugs they'd have to liquify it so it would just be easier to ask for urine instead of stool.
That would refer to having another stool test (testing fecal matter for blood).A re-test is a do over.
They test stool for a lot of things, but drugs, so far as I know, are not one of the things they test it for. (Mostly stool samples are tested for bacteria and blood.) To test stool for drugs they'd have to liquify it, for starters. It would just be easier to ask for urine instead of stool.
Blood tests would not show this, stool tests may help. If he was contaminated he would be sick continuously, not off and on, so I don't think he is contaminated , it could be that he gets recurrent infections from contamination of what he heats or contamination of things he touches, which would make exposing of the waste properly very important. If it occurs again he can have a blood test called a complete blood count, and blood culture, as well as a stool test
Black/green stool would indicate blood somewhere in the GI tract. It usually would have "coffee grinds" look to it. See a doctor, you probably have an intestinal ulcer or severe irritation. It will probably be taken care of with some prescription meds.Different foods will turn your stool different colors. If you eat a lot of asparagas it will turn your stool green. A lot of black licorice can turn your stool purple to black. If it is always black you might want to ask a doctor.
Your period shouldn't be like water, but watery in the sense of liquid is normal - your menstrual flow is made up of blood, tissue, mucus and discharge, but it's normal for there to be more blood than anything else which would make it more liquid.
Your body takes on excess water and gets rid of what it doesn't need. If excess water was allowed to accumulate in the blood, you would have dilute, watery blood, which would not do its job properly.