In 2014, the Centers for Disease Control and Prevention (CDC) updated its guidelines for HIV tests and screenings. Thanks to technological advances, today there are so-called "fourth generation" antigen/antibody tests available to more accurately diagnose HIV. These tests, paired with additional screening tools, can help providers choose the correct treatment strategy for their patients. The tests can also help arm patients with information they need to make healthy decisions moving forward.
Today, all newly diagnosed patients with HIV will need a variety of tests to accurately confirm diagnosis, evaluate the amount of virus in the blood and measure immune function. Previous diagnostic tests for HIV (such as the Western blot and HIV-1 immunofluorescent assay [IFA]) fell out of favor with the CDC because they were not sensitive enough to detect new infections. In contrast, newer tests screen for two kinds of proteins -- antigens and antibodies -- produced as a result of HIV infection. These tests can detect an infection within a few weeks of exposure, reducing the risk of a false-negative result.
There are also many basic screenings that should be included in the first appointment with a newly diagnosed patient living with HIV. These include screenings for depression and other sexually transmitted infections.
On top of all the basic tests, providers have to be cognizant of a patients' insurance situation and risk behaviors -- these can influence which additional tests and screenings are appropriate for each patient, said Peter Meacher, M.D., of the Callen-Lorde Community Health Center, New York, NY.
In addition to basic tests that measure immune function and viral load, the first appointment after diagnosis should also include important screenings for substance abuse, mental health and housing status, said Laura Cheever, M.D., associate administrator of the HIV/AIDS Bureau, Department of Health at the Health Resources and Services Administration.
Basic Tests for Every Patient
The National Institutes of Health and Department of Health and Human Services recommend recommend the following tests for all newly diagnosed HIV patients:
- HIV antibody testing: This test screens for antibodies that the body produces as a response to the HIV virus. If the virus is detected, a blood sample will be further analyzed to determine if the patient is infected with the HIV-1 or HIV-2 strain.
- CD4+ cell count: This lab test measures the number of CD4+ cells in a patient's blood, which is an important indication of how well the immune system is fighting the HIV virus.
- Plasma HIV RNA: This test helps determine the amount of virus in the blood (viral load). Clinicians need to know a patient's starting viral load to measure if treatment is working.
- Other serologies: Providers should also test for viral hepatitis (A, B and C).
- Other workups: A complete workup should include blood count, chemistry profile, transaminase levels, blood urea nitrogen (BUN), creatinine and urinalysis.
- Fasting blood glucose and serum: The HIV virus can affect a patient's metabolism, which is why recommendations include tests for glucose and lipid levels. Specifically, HIV can increase the chances of developing diabetes and heart disease.
- Genotypic resistance testing: All patients should be screened for drug resistance. Today, there are many strains of HIV that do not respond to approved medications. This test will help determine the best course of treatment.
Routine Behavior Screenings
Behavior screening and additional risk-based testing are important aspects of caring for a newly diagnosed patient. All patients should be screened for depression, and depending on risk factors, some patients should be additionally screened for other sexually transmitted infections and anal cancer.
- Patient Health Questionnaire-2: This screening exam is typically given during the first doctor's appointment after a positive HIV diagnosis. Two simple questions can help determine a patient's likelihood of depression.
- Sexually transmitted infections: Although guidelines recommend that newly diagnosed HIV patients be tested for other sexually transmitted infections, it is extremely important to conduct "four-site" testing for men who have sex with men, said Meacher. Four-site testing includes urine, mouth and anal tests for gonorrhea and chlamydia, as well as a blood test for syphilis.
- Anal cancer: The AIDS Institute recommends anal cancer screenings for all HIV-positive patients, especially men who have sex with men, Meacher said. However, Meacher pointed out that approximately 30% to 50% of anal pap smears show some kind of abnormality. Ideally, patients should receive a follow up tests called High Resolution Anoscopy (HRA), but there are very few care centers equipped to conduct this test, Meacher said. Unfortunately, many patients -- especially those in rural areas -- may have trouble receiving the follow up care they need.
- Smoking: Patients with HIV have higher rates of lung cancer, even in studies that controlled for smoking, said Cheever. Tobacco use is high among people with HIV, and it is important to emphasize smoking cessation options to reduce a patient's chance of developing lung cancer, she continued.
Ideally, all of these tests should take place during the first appointment after a definitive diagnosis, said Meacher. However, if a patient is uninsured, there are some tests that can wait until the patient becomes enrolled in an insurance plan and is able to afford potential copays or other medical expenses.
For example, drug resistance testing can be expensive, and might create a financial burden for some patients, he continued.
The Ryan White Program provides $2.3 billion in annual investments so that uninsured or underinsured patients can get all tests recommended by the Department of Health and Human Services, said Cheever.
"The timing of these tests may depend on getting practical details sorted," Meacher points out.