Which of the following terms refers to conditions assumed to exist but not yet confirmed?

The term that refers to conditions assumed to exist but not yet confirmed is "probable." In a clinical context, "probable" indicates that there is a strong suspicion or indication that a certain condition may be present based on available evidence, but definitive confirmation has not yet been achieved. This term is often used in clinical assessments to guide further investigations or management plans while acknowledging the need for additional validation.

The other options represent different states of diagnosis: "diagnosed" refers to conditions that have been confirmed through tests or clinical evaluation; "confirmed" clearly implies that a diagnosis has been established as accurate; and "sustained" typically relates to the maintenance of a condition over time rather than its initial assessment. Thus, "probable" is specifically the term aligned with uncertainty and the presumption of existence without confirmation.