21 CFR §516.131

1. (a)If a request for determination of eligibility for indexing contains all of the information required by § 516.129, FDA shall file it, and the filing date shall be the date FDA receives the request.
2. (b)If a request for a determination of eligibility lacks any of the information required by § 516.129, FDA will not file it, but will inform the requestor in writing within 30 days of receiving the request as to what information is lacking.