A screen test for detection of human immunodeficiency virus (HIV) reveals a positive ELISA exam. Which of following tests will be used to confirm diagnosis of HIV?

Correct Answer: A. Indirect immunofluorescence assay (IFA)

The indirect immunofluorescence assay (IFA) test and Western Blot test result are considered as confirmatory for HIV. An initial HIV test usually will either be an antigen/antibody test or an antibody test. If the initial HIV test is a rapid test or a self-test and it is positive, the individual should go to a health care provider to get follow-up testing. If the initial HIV test is a laboratory test and it is positive, the laboratory will usually conduct follow-up testing on the same blood sample as the initial test. Although HIV tests are generally very accurate, follow-up testing allows the health care provider to be sure the diagnosis is right.

• Option B: CD4-to-CD8 ratio monitors the progression of HIV. A normal CD4/CD8 ratio is greater than 1.0, with CD4 lymphocytes ranging from 500 to 1200/mm 3 and CD8 lymphocytes ranging from 150 to 1000/mm 3. If the ratio is higher than 1, it means the immune system is strong and the client may not have HIV. If the ratio is less than 1, the client may have HIV.
• Option C: Radioimmunoprecipitation assay (RIPA) test detects HIV protein rather than showing antibodies. Radioimmunoprecipitation assay buffer (RIPA buffer) is a lysis buffer used for rapid, efficient cell lysis and solubilization of proteins from both adherent and suspension-cultured mammalian cells.
• Option D: p24 antigen assay quantifies the amount of HIV viral core protein. One distinctive HIV antigen is a viral protein called p24, a structural protein that makes up most of the HIV viral core, or ‘capsid’. High levels of p24 are present in the blood serum of newly infected individuals during the short period between infection and seroconversion, making p24 antigen assays useful in diagnosing primary HIV infection.