The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing . During digestion, lactose is broken down into the monosaccharides glucose and galactose by the intestinal enzyme lactase. Lactose-intolerant patients have a deficient or absent lactase enzyme.
Bacteria metabolize the lactose, producing gas and acid products.
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.