Serum IgE Testing

indications

• Severe eczema or dermatographism preventing skin testing
• Patient cannot stop antihistamines
• History of severe allergic reactions to skin testing
• Complement to skin testing results
• Component-resolved diagnostics for food allergies

advantages

• No risk of systemic reaction from testing
• Not affected by medications
• Can test for many allergens at once
• Useful for component-resolved diagnostics

total Ige

• Measures total IgE level in blood
• Elevated levels suggest allergic tendency
• Not diagnostic for specific allergies
• Can be elevated in non-allergic conditions

specific Ige

• Measures IgE to specific allergens
• Reported in kU/L or classes (0-6)
• Higher levels suggest stronger sensitization
• Must correlate with clinical history

component

• Identifies specific proteins within allergens
• Useful for food allergies (e.g., peanut components)
• Can help predict risk of severe reactions
• Aids in determining if oral food challenge is needed

levels

• Class 0: <0.35 kU/L - Negative
• Class 1: 0.35-0.69 kU/L - Low positive
• Class 2: 0.70-3.49 kU/L - Moderate positive
• Class 3: 3.50-17.49 kU/L - High positive
• Class 4-6: Very high positive

correlation

• Higher levels generally indicate stronger sensitization
• Doesn't always predict severity of clinical reactions
• Must be interpreted with clinical history
• Component testing can provide more specific information

food

Component-resolved diagnostics can help determine if oral food challenge is safe

inhalant

Useful when skin testing cannot be performed

drug

Limited availability for drug allergy testing

venom

Can complement skin testing for insect venom allergies