When a medical expert is uncertain while testifying, they should admit uncertainty to maintain credibility and ethical integrity. Guessing can lead to misinformation and may be legally and professionally damaging. Admitting uncertainty demonstrates honesty and protects the expert's impartiality, ensuring the court receives accurate and reliable information. This approach upholds the standard of evidence-based practice and respects the legal process. Remaining silent or providing irrelevant information fails to clarify facts and impedes the judicial purpose. Transparency in knowledge limits is critical in expert testimony.

Reference: Principles and Practice of Forensic Medicine, Jason Payne-James, 4th Edition.