“Is a little blood in stool serious?”

Blood in the stool have multiple etiologies. They are hemorrhoids (internal or external), anal fissure, diverticulosis, irritable bowel disease (IBD), cancer as well as other causes. Blood in the stool can cause anemia, feeling light-headed, in the extreme of cases shortness of breath, chest pain or abdominal pain. Sometimes the blood is intermittent. I recommend for you to see a gastroenterology and together you decide to have a colonoscopy or an upper endoscopy to rule out cancer and ulcers. Thank you.

Possibly. You need to have a physical examination and possibly scoped.

This is a very nonspecific result. It might mean nothing, it might be from some benign bleeding source, or (worst case scenario) it could indicate colon cancer.
The positive test needs to be addressed by the person who ordered it.