Sub-Investigators and Medical Cover

Part of Principal Investigator (PI) Training: The Investigator's Accountability.

About 4 minutes. Free, in your language, no account needed.

Why this matters

A trial runs continuously. You do not. Nights, weekends, leave, conferences, illness — a participant can have a serious adverse event during any of them, and someone medically qualified has to be reachable and authorized to act. That arrangement is not an administrative afterthought. It is the mechanism by which §2.7.1 keeps being satisfied while you are asleep.

What a sub-investigator is, and is not

The Glossary defines a sub-investigator as a member of the trial team designated and supervised by the investigator to perform trial-related procedures and make trial-related decisions — with associates, residents and research fellows given as examples.

Three consequences follow, and each one is a finding waiting to happen if you miss it.

1. Designation is an act, not an assumption. A colleague is not a sub-investigator because they are a colleague, or because they happen to be on shift. They are one because you designated them, in writing, for named tasks.
2. Supervision continues. Designating a sub-investigator does not divide the responsibility with them. It adds a person you now supervise.
3. Seniority is irrelevant to the structure. A departmental chair acting as a sub-investigator on your trial is supervised by you for that trial. This is uncomfortable in some institutions and it is still what the guideline says.

Who may make trial-related medical decisions

Section 2.7.1(a) is the sentence that makes this a physician's course. A qualified physician — or dentist, or other healthcare professional where applicable regulatory requirements permit — who is an investigator or sub-investigator for the trial should be responsible for all trial-related medical decisions.

Note what that excludes. Not the coordinator, however experienced. Not a colleague who is medically qualified but was never designated. Not the sponsor's medical monitor, whose advice is advice.

Section 2.7.1(b) then makes room for reality: other qualified healthcare professionals may be involved in participants' medical care. Your ward team still treats your patient. What they cannot do is make the trial-related medical decision — the eligibility call, the causality assessment, the decision to unblind, the decision to discontinue investigational product.

Building a cover plan that actually holds

A cover plan is a short written arrangement, agreed before enrollment, that answers four questions.

• Who covers, by name? At least one designated sub-investigator, ideally two, with the same qualification and training status as you.
• How are they reached? One number that reaches a covering investigator at any hour, known to the coordinator and written where the on-call team can find it at 3 a.m. — not only in the trial master file.
• What may they decide alone? In practice: emergency medical care, urgent unblinding, immediate safety measures, and the initial assessment of a serious adverse event. Anything that can safely wait until you are back, waits.
• How does it get back to you? A single rule — the covering investigator documents the decision the same day and notifies you at the next working opportunity — closes the loop that inspectors look for.

Test the plan before you need it. Ask your coordinator to call the cover number on a Saturday during start-up. A cover plan that has never been dialed is a document, not a plan.

The failure this prevents

The recurring pattern is not a wrong medical decision. It is a delayed one: a serious event on a Friday evening, a coordinator who cannot reach a designated investigator, an assessment written on Monday by someone who was not there, and a source record that cannot say who made the medical decision or when.

Every part of that is preventable at start-up, in about twenty minutes, by naming two people and one telephone number.

Key takeaways

• A sub-investigator is designated and supervised by you; the designation is a documented act, not a job title or a shift pattern.
• Under §2.7.1(a), trial-related medical decisions belong to a qualified physician who is an investigator or sub-investigator on that trial.
• Under §2.7.1(b), other qualified professionals may be involved in the participant's medical care — which is not the same as making trial-related decisions.
• Agree a named, reachable, documented cover plan before enrollment, and test the number.