Table 2.

Diagnostic criteria for the interpretation of oral food challenges (OFCs) in patients with a history of possible or confirmed FPIES (from reference [1]).

Major criterion

•   Vomiting in the 1 to 4 h period after ingestion of the suspect food and the absence of classic IgE-mediated allergic skin or respiratory symptoms.

Minor criteria

Lethargy; Pallor; Diarrhea 5–10 h after food ingestion; Hypotension; Hypothermia; An increased neutrophil count of >1500 neutrophils above the baseline count.

The OFC will be considered diagnostic of FPIES (i.e., positive) if the major criterion is met with ≥2 minor criteria. However, we would suggest two important caveats to these criteria: (1) With the rapid use of ondansetron, many of the minor criteria, such as repetitive vomiting, pallor, and lethargy can be averted, and (2) not all facilities performing challenges have the ability to perform neutrophil counts in a timely manner. Therefore, the treating physician might decide that a challenge be considered diagnostic in some instances, even if only the major criterion was met. However, in challenges performed for research purposes, providers should adhere to stringent criteria for challenge positivity.