Whether done over the phone, online, or in person, collecting identifiable private information for study screening purposes requires informed consent (and HIPAA authorization, if applicable). This consent/authorization can be much shorter than for the form for the study itself and the IRB can waive the requirement for a signature, if needed. The IRB has a template for a verbal screening consent and HIPAA authorization.
Consent and authorization must be done, however, and the need for such screening must be described in the eIRB smartform. An alternative would be to describe the inclusion/exclusion criteria to a potential subject, and then simply ask them if they feel they meet the criteria and would like to schedule their first study visit. Since you would not be recording any identifiable private information about that person, no consent/authorization would be needed. Note that unique study ID numbers, if linked to identifiers via a key, would be considered identifiers and prompt the need for informed consent/authorization.
Please see the IRB webinar on Screening Procedures: What is Covered by a Partial HIPAA Waiver and What is Not (recording/slides), for more information.
From the Office of the Institutional Review Board