Evaluation of the Interference of Lipemia and Hemolysis in the Detection Limit of Anti-HIV-1 Antibodies.

Background: The instructions of manufacturers of methodologies for anti-HIV-1/2 antibodies screening tests re-commend avoiding analyzing blood samples with hemolysis or lipemia, but they do not mention references about scientific studies evaluating their interference. The increased need for an opportune detection of HIV infection to avoid its spread has led to public health institutions including routine HIV screening even in internal medicine and emergency rooms. Nevertheless, these blood samples are usually associated with the presence of lipemia and/ or hemolysis, leaving doubt for probable misinterpretations. This fact highlights the need for applying verification techniques, established under the internal methodological conditions of each laboratory, in order to increase the coverage of HIV screening and to ensure the reliability of their results.

Methods: Following the ethics committee approval and patient's informed consent, a confirmed anti-HIV-1 positive human serum (undetectable viral load and p24 antigen, and stable total lymphocytes > 30%) was obtained. This work describes techniques for the semiquantitative analysis of anti-HIV antibodies of three commercial HIV-screening methodologies (immunochromatography, enzyme-immunoassay and chemiluminescence) and to deter-mine the detection limit of these screening tests, as well as evaluating the maximum concentration of total lipids and of free hemoglobin that do not interfere in the detection limits.

Results: The highest analyzed concentration of total lipid (870 mg/dL) did not interfere with the detection limits of anti-HIV-1 antibodies in any of the evaluated methodologies. Free hemoglobin presented interference at different concentrations depending on the methodology: immunochromatography (0.57 g/dL)), enzyme-immunoassay (8.6 g/dL), and chemiluminescence (11.5 g/dL)).

Conclusions: Concentrations of lipemia above postprandial levels or hemolysis induced by experimental manipulation might not interfere with HIV-serological screening. Determining the maximum permissible limits of lipemia and hemolysis by each manufacturer or laboratory based on an internal evaluation of their serological methodology would increase the reliability of HIV-diagnosis in internal medicine and emergency rooms and in patients with dyslipidemia or physiological hemolysis.