Methacholine challenge testing sequence

* The choice of the FEV₁ value considered a contraindication may vary from 60 to 70% of predicted. An FEV₁ <1.5 L in adults is an additional contraindication.
¶ 400 microg is roughly equivalent to 16 mg/mL.
Δ The final dose may vary depending on the dosing schedule used. Final doses discussed in this statement are 16, 25, and 32 mg/mL.