Because if you are allergic to shellfish you most likely are allergic to iodine or betadine which is what they use to prep your arm with when they draw your blood.
Betadine
No, Betadine does not contain Alcohol.
Betadine is an antiseptic that is used when creating a sterile field. Betadine works by cleaning the skin before a procedure is performed.
You should not use Betadine if a patient is allergic to iodine. Betadine contains approximately 1% iodine, which could be enough to cause an allergic reaction.
When using betadine scrub on your dog, dilute it to one part betadine to ten parts water. After the solution is diluted, it will have a weak tea color. Applying betadine undiluted to your dogs skin can cause burning and irritation.
The trade name for povidone iodine is Betadine.
Kills germs in minor cuts, scrapes, and burns.
Betadine, an ointment applied to a patient on a surgical spot before operation, was invented by the company, Purdue Pharma.
Betadine is an ingredient present in many natural treatments for ear infections in dogs.
The plural of shellfish is shellfish.
Betadine is a compound. It is composed of the chemical povidone-iodine, which is a complex of the polymer povidone (polyvinylpyrrolidone) and the element iodine.