HIV testing without consent in critically ill patients.

CONSIDER THE FOLLOWING 3 NEWLY ADMITTED PAtients. The first patient has marked hypoxemia requiring mechanical ventilation and is found to have nonspecific, bilateral, alveolar infiltrates on chest radiography. The second patient has had a severe change in mental status and on brain imaging has an enhancing lesion exerting a mass effect. The third patient has high fevers, ventilator-dependent respiratory failure, and diffuse nodular infiltrates on chest radiography, with negative blood, urine, and sputum cultures after 48 hours. In each of these cases, the next steps in physicians’ diagnostic and therapeutic algorithms could be usefully informed by knowledge of the patients’ immunocompetency. Knowing that these patients had recently used immunosuppressive therapies, or were infected with the human immunodeficiency virus (HIV), would substantially increase the probabilities of Pneumocystis jiroveci pneumonia in the first patient, toxoplasmosis in the second patient, and disseminated fungal or mycobacterial infections in the third patient. Indeed, knowledge of immunocompromise would result in disease probabilities that surpass many clinicians’ treatment thresholds, leading them to treat these conditions empirically, rather than await the results of bronchoscopy in the first patient, brain biopsy in the second, or lung biopsy in the third. Because of the complication risks and financial costs of these procedures, some clinicians may even forgo them entirely unless or until evidence arose that the patients were not responding to empirical therapy. Thus, knowledge of immunosuppression would lead to earlier application of potentially life-saving therapies, and might reduce the costs and complications associated with potentially unnecessary procedures. Speaking with family members or other health care professionals should reveal the use of immunosuppressive drugs; but for many patients, a history of HIV testing may be absent or unavailable. Because laws and standards of practice currently prevent HIV testing without specific consent, emergency HIV testing, which can be completed in 10 to 30 minutes, cannot proceed among patients who are mentally incompetent (ie, those lacking the capacity to make informed decisions). Forced to treat these patients without knowledge of HIV status, many physicians might order tests for presumed surrogate markers of HIV-induced immunocompromise. However, among the potential surrogate markers, absolute lymphocyte counts provide little knowledge of immune function or HIV status, and CD4 lymphocyte counts are unreliable in critically ill patients. Although the ratio of CD4:CD8 lymphocytes may be preserved in critical illness, testing for this ratio in lieu of formal HIV testing represents a deceitful attempt to get around current restrictions.