A study takes body-composition measurements at baseline using a DEXA scanner.

To properly associatebody-composition data(from a DEXA scanner) with other study data, both thesubject numberand thevisit numberare required.

According to theGCDMP (Chapter: Data Management Planning and Study Start-up), every clinical data record must beuniquely identifiable and linkableto a specific subject and study event. Thesubject numberidentifies the participant, while thevisit numberdefines the temporal context in which the measurement was taken.

Without both identifiers, data integration becomes ambiguous—especially if multiple assessments occur over time (e.g., baseline, week 12, end of study). Including both ensuresdata traceability, integrity, and alignmentwith the protocol-defined schedule of events.

Study number (option A) alone does not distinguish between visits or subjects, and visit number alone (option C) lacks linkage to the individual participant.

Reference (CCDM-Verified Sources):

SCDM Good Clinical Data Management Practices (GCDMP), Chapter: Data Management Planning and Study Start-up, Section 4.4 – Data Linking and Identification Requirements

ICH E6 (R2) GCP, Section 5.5.3 – Data Traceability Principles

FDA Guidance for Industry: Computerized Systems Used in Clinical Investigations – Data Identification Requirements