Component-Resolved Diagnostics (CRD)

Whole-allergen tests and component-resolved diagnostics do not compete for the title of “most accurate.” They measure different levels of sensitization. A whole extract can show that IgE recognizes material from a food or pollen source; a component test can sometimes identify the particular protein pattern behind that result. The additional detail matters only when it changes counseling, the need for avoidance, or whether a supervised challenge is reasonable.

The most useful order is history first, existing results second, and the unresolved decision third. For example, the clinician may be separating primary food sensitization from pollen-related cross-reactivity, assessing whether two related foods should be discussed separately, or deciding whether more information would improve an oral food challenge risk assessment. Ordering every available component creates more results but not necessarily more clarity.

A component value still cannot predict the exact symptoms or severity of a future reaction. It must be reconciled with foods currently eaten, the form and amount involved in prior reactions, cofactors, and test trends. Review the difference between sensitization and clinical allergy in the allergy blood testing guide before using a molecular result to remove a tolerated food.