Source Data / Source Documents

Source data are the original clinical findings, observations, and other activities recorded during a trial — the hospital record, the lab report, the ECG trace, the participant diary, the pharmacy dispensing log. Source documents are where those data first appear. Everything reported in the case report form is derived from them, which is why ICH E6 requires source data to satisfy ALCOA-type attributes just as GMP records do.

The governing rule is that the first capture is the source. If a measurement is written on a worksheet and later transcribed into the CRF, the worksheet is the source and must be retained. If data are entered directly into an electronic CRF with no prior written record, the eCRF field is the source — and the sponsor must have specified that in advance, because it changes what has to be preserved and made available for inspection.

Source data verification is the check that reported data match the source. Under ICH E6(R3) and risk-based monitoring, blanket 100% verification of every field is no longer the expectation; effort concentrates on the data that matter — primary endpoints, eligibility, safety reporting, and informed consent — with centralised statistical monitoring detecting anomalies across sites that on-site review would miss.

• —Source = the first capture: hospital records, lab reports, traces, diaries, dispensing logs.
• —CRF data are derived from source; source must be retained and available for inspection.
• —Direct-entry eCRF fields can be the source only if the sponsor defined that in advance.
• —ALCOA attributes apply to clinical source data as they do to GMP records.
• —Risk-based monitoring targets verification at endpoints, eligibility, safety, and consent.
• —Missing or inaccessible source documents are among the most serious GCP inspection findings.

ICH E6(R3) Good Clinical Practice (source data and essential records); 21 CFR Part 312 (sponsor and investigator record-keeping); EU Regulation (EU) No 536/2014; FDA guidance on Electronic Source Data in Clinical Investigations (2013).