Implications of an indeterminate HIV antibody result - a case series

In Sri Lanka Immunoassays using either viral lysate (Western Blot) or recombinant/synthetic antigen (Line Immunoassay) for anti-HIV capture are still the preferred methods to confirm HIV infection. Three patients infected with HIV-1 presented with Acquired Immunodeficiency Syndrome (AIDS) defining illnesses. Laboratory tests were performed using the routine commercial kits on multiple sera of one patient and same sera from the other two. All patients were strongly positive on the Enzyme Linked Immuno Sorbent Assay (ELISA) test. Yet, HIV-1 infection could not be confirmed using the routine Line Immunoassay. Eventually HIV infection was confirmed in two patients using the Western blot assay but in one patient that was also indeterminate. We were unable to test further due to non-availability of other tests such as nucleic acid testing (NAT) assays to confirm the presence of HIV RNA. This highlights the fact that in resource poor countries, indeterminate results may delay the diagnosis of HIV, if only Line Immunoassays are available. Some end stage HIV/ AIDS patients may not produce antibodies to specific HIV antigens and may give indeterminate or negative results.

DOI: http://dx.doi.org/10.4038/sljv.v2i1.5402

Sri Lanka Journal of Venereology Vol.2(1) 2009 pp.25-28