NEW From Medicaid for billing H1N1 administration Medicaid is not not carrying the G9141 on their procedure code file. Physicians must use 90470. The billing information for H1N1 has a $13.23 administration fee. Medicaid is increasing that fee to $17.85 for patients under age 19, consistent with the administration fee for this age group for seasonal flu. The fee remains $13.23 for age 19+.