Allergy testing can be conducted by measuring which type of blood levels?

Allergy testing in veterinary medicine often involves measuring specific immunoglobulin E (IgE) levels or other related antibodies in the blood, which are indicators of an allergic response. A blood titer refers specifically to the concentration of these antibodies and can help assess an animal's sensitivity to particular allergens. The higher the titer, the more antibodies are present, suggesting that the animal has a higher likelihood of being allergic to that specific allergen.

Other options do not pertain to allergy testing. Blood glucose measures sugar levels in the blood and is used to diagnose diabetes, while blood pressure measures the force of blood against artery walls, relevant for cardiovascular health. Blood ammonia levels indicate liver function and are unrelated to allergy responses. Therefore, the measurement of blood titer is the most relevant and effective method for conducting allergy testing in animals.