Image by Wolfgang Ihloff in Wikipedia For inhalant allergies, there is a high agreement (~80-90%) in results found between skin prick and blood testing . However, occasionally the results may differ quite significantly... usually in these situations, the skin prick test comes back positive for something whereas the blood test comes back negative or normal. It's also possible that both skin prick and blood testing may come back normal even if a patient is truly allergic. Why? Bef…