Services in which a specialist's opinion or advice is requested are known as what?

When referring to services in which a specialist's opinion or advice is requested, the term "consultation" is most appropriate. A consultation typically involves an expert providing their insights or recommendations regarding a patient's condition or treatment options after being requested to do so.

During a consultation, the specialist reviews the patient's medical history and current health issues, usually after being referred by another healthcare provider, but the key aspect is that the specialist is giving their professional advice on the situation. This differentiation is crucial in the healthcare context, as consultations emphasize the idea of seeking a second opinion or specialized knowledge, which is essential for making informed decisions regarding patient care.

The other options—diagnosis, referral, and evaluation—while related to the process of patient care, denote different stages or actions in the healthcare continuum rather than the specific act of obtaining a specialist's opinion. For instance, diagnosis refers to identifying a condition based on signs and symptoms, a referral involves directing a patient to a specialist, and evaluation pertains to assessing a patient's condition or treatment needs without necessarily involving an expert's opinion. Thus, consultation clearly represents the service in question.