Items in AFP with MESH term: Immunoassay
Newsletter - AAFP News: AFP Edition
ABSTRACT: Urine drug screening can enhance workplace safety, monitor medication compliance, and detect drug abuse. Ordering and interpreting these tests requires an understanding of testing modalities, detection times for specific drugs, and common explanations for false-positive and false-negative results. Employment screening, federal regulations, unusual patient behavior, and risk patterns may prompt urine drug screening. Compliance testing may be necessary for patients taking controlled substances. Standard immunoassay testing is fast, inexpensive, and the preferred initial test for urine drug screening. This method reliably detects morphine, codeine, and heroin; however, it often does not detect other opioids such as hydrocodone, oxycodone, methadone, fentanyl, buprenorphine, and tramadol. Unexpected positive test results should be confirmed with gas chromatography/mass spectrometry or high-performance liquid chromatography. A positive test result reflects use of the drug within the previous one to three days, although marijuana can be detected in the system for a longer period of time. Careful attention to urine collection methods can identify some attempts by patients to produce false-negative test results.
What Is New in HIV Infection? - Article
ABSTRACT: Human immunodeficiency virus (HIV) prevention and treatment updates include screening recommendations, fourth-generation testing, preexposure prophylaxis, and a paradigm shift; treatment is prevention. The U.S. Preventive Services Task Force recommends routine HIV screening in persons 15 to 65 years of age, regardless of risk. Fourth-generation testing is replacing the Western blot and can identify those with acute HIV infection. The U.S. Food and Drug Administration approved the OraQuick In-Home HIV Test; however, there are concerns about reduced sensitivity, possible misinterpretation of results, potential for less effective counseling, and possible cost barriers. Preexposure prophylaxis (effective in select high-risk adult populations) is the combination of safer sex practices and continuous primary care prevention services, plus combination antiretroviral therapy. Concerns for preexposure prophylaxis include the necessity of strict medication adherence, limited use among high-risk populations, and community misconceptions of appropriate use. Evidence supports combination antiretroviral therapy as prevention for acute HIV infection, thus lowering community viral loads. Evidence has increased supporting combination antiretroviral therapy for treatment at any CD4 cell count. Resistance testing should guide therapy in all patients on entry into care. Within two weeks of diagnosis of most opportunistic infections, combination antiretroviral therapy should be started; patients with tuberculosis and cryptococcal meningitis require special considerations.