Although it is commonly said that the notions of sensitivity and specificity were first defined by Jacob Yerushalmy in 1947, the sensitivity and specificity of diagnostic tests have been assessed as far back as the early 1900s. These notions share a common origin with the development of serology. They were originally immunologic concepts, closely associated with the development of complement fixation reactions for syphilis. Here, the authors trace how immunologic sensitivity and specificity were transformed into diagnostic sensitivity and specificity. By relocating the origins of these concepts to the early 20th century, they highlight how these origins were bound to then-commonplace assumptions about specific infectious disease entities.

Tenofovir-based antiretroviral therapy (ART) has become first-line in all major HIV treatment guidelines. Compared with tenofovir disoproxil fumarate (TDF), tenofovir alafenamide (TAF) has a favorable renal and bone safety profile, but concerns about metabolic complications remain.

The environment in which physicians practice and patients receive care continues to change. Increasing employment of physicians, changing practice models, new regulatory requirements, and market dynamics all affect medical practice; some changes may also place greater emphasis on the business of medicine. Fundamental ethical principles and professional values about the patient-physician relationship, the primacy of patient welfare over self-interest, and the role of medicine as a moral community and learned profession need to be applied to the changing environment, and physicians must consider the effect the practice environment has on their ethical and professional responsibilities. Recognizing that all health care delivery arrangements come with advantages, disadvantages, and salient questions for ethics and professionalism, this American College of Physicians policy paper examines the ethical implications of issues that are particularly relevant today, including incentives in the shift to value-based care, physician contract clauses that affect care, private equity ownership, clinical priority setting, and physician leadership. Physicians should take the lead in helping to ensure that relationships and practices are structured to explicitly recognize and support the commitments of the physician and the profession of medicine to patients and patient care.

Immediate initiation of antiretroviral therapy (ART) regardless of CD4 cell count reduces risk for AIDS and non-AIDS-related events in asymptomatic, HIV-positive persons and is the standard of care. However, most HIV-positive persons initiate ART when their CD4 count decreases below 500 × 109 cells/L. Consequences of delayed ART on risk for non-AIDS-defining and AIDS-defining cancer, one of the most common reasons for death in HIV, are unclear.

The widespread availability of SARS-CoV-2 antibody tests raises important questions for clinicians, patients, and public health professionals related to the appropriate use and interpretation of these tests. The Scientific Medical Policy Committee (SMPC) of the American College of Physicians developed these rapid, living practice points to summarize the current and best available evidence on the antibody response to SARS-CoV-2 infection, antibody durability after initial infection with SARS-CoV-2, and antibody protection against reinfection with SARS-CoV-2.