In Medicine, what is a Source Document?

A source document is an original document utilized in a clinical trial. Source documents are a critical part of amassing information which is used to reach a conclusion and they may be audited by investigators who determine whether or not the outcome of the clinical trial can withstand rigorous scientific evaluation. These documents must be carefully handled because in addition to being critical to the trial itself, they also contain confidential patient information.

In order to be considered a source document, a document must be an original or a certified copy. This is designed to prevent situations in which information is falsified for the purpose of manipulating study results, and to avoid problems such as poor copies which are difficult to read and may be confusing for people going over trial data. Many trials use a standardized source document format, such as a single basic form for medical records, to make it easy to review source documents.

Source documents include the results of medical imaging studies such as x-rays and MRIS, lab reports, medical records, printouts from diagnostic evaluations such as spirometry and electrocardiography, copies of informed consent forms, diaries kept by patients to record their responses to the trial, notes from researchers, and so forth. Each patient has a file filled with source documents and these files are stored in a secured area which can only be accessed by authorized personnel. A source document can contain patient information as well as proprietary information about the device or drug being studied, which makes security critical.

As researchers evaluate the outcome of the clinical trial for the purpose of writing up results, they refer to the source documents. These same documents are also used by auditing authorities who confirm the outcome of the trial. If for some reason an original is not available and a certified copy must be used, the auditor may want an explanation for the substitution, as the loss or theft of an original document could compromise a study.

Because a source document will be reviewed not only by researchers but by auditors and other personnel, it must be clearly laid out and well presented. Researchers try to avoid using shortcuts such as abbreviations and they must fill out documents neatly and clearly. If source documents are confusing or poorly organized, it can reflect poorly on the study itself and auditors and other reviewers may have concerns about the integrity of the data and the effectiveness of the study.