TABLE II.

Methods for measuring and reporting core and supplemental biomarker outcomes

Serologic multiallergen screen	Preferred method: adults—Phadiatop; children— Phadiatop plus fx5 food allergen mix Report as kUa/L (with 0.35 kUa/L as the cutpoint for presence of atopy)
Total serum IgE	Preferred method: any FDA-cleared immunoassay
Allergen-specific IgE	Preferred method: serum immunoassay Preferred assay: ImmunoCAP (Phadia) Alternative assays: HYTEC (Hycor) Immulite (Siemens) Note: skin prick tests have no single generally accepted technique
Feno	Preferred method: ATS/ERS guidelines1–3 for measurement at 50 L/s Report whether online or offline method was used Report as ppb in exhaled breath (<25 ppb indicates normal value)
Sputum eosinophils	Preferred method: whole expectorate Alternative method: sputum plug Report as: Preferred: eosinophil percentage per mL of sputum Alternative: total eosinophils per μL of sputum
CBC (total eosinophils)	Method: CBC by automated analyzer Report as absolute eosinophil count (eosinophils × 109/L) Percentage eosinophils is not recommended
Urinary LTE4	Preferred method: random urine sample; mass spectroscopy Report as pg/μg creatinine (<50 pg/μg indicates normal value)