Three out of every 20 samples from HIV-infected patients had discrepant HDL cholesterol values with respect to the ultracentrifugation method. Overestimation was associated with high C-reactive protein concentrations and underestimation with plasma γ-globulin concentrations, an effect that was amplified by any of the storage conditions tested. Caution is needed when using the synthetic polymer/detergent homogeneous method for direct measurement of HDL cholesterol concentrations in HIV-infected

patients. This assay is of limited use in clinical trials in which frozen samples are analysed. Pro-atherogenic metabolic disturbances in HIV-infected patients are increasingly a clinical concern because of the higher cardiovascular disease risk Selleck PD332991 observed in these patients with respect to uninfected populations [1]. Low high-density lipoprotein (HDL) cholesterol concentrations are common and characterize dyslipidaemia in patients undergoing long-term antiretroviral therapy

[2], resulting in an increased incidence of cardiovascular events [3]. Consequently, SP600125 clinical laboratories should provide accurate and reliable measurements of HDL cholesterol as part of the continuous management and evaluation of these patients [4]. Automated homogeneous assays have been adopted for the direct quantification of HDL cholesterol in clinical laboratories. However, although these methods show good agreement with reference methods in healthy subjects [5], falsely low HDL cholesterol concentrations have been observed in patients with different disease states [6,7]. HIV

infection results in persistent inflammatory stimuli [8] and HDL particles have been reported to lose their atheroprotective properties (i.e., cholesterol efflux capacity, and anti-oxidative and anti-inflammatory activities) during inflammation and could be modified during the acute response phase [9]. It is unknown whether major changes in HDL particles are elicited by HIV infection and data on the impact of such changes on HDL cholesterol measurements obtained using the homogeneous assay have not been properly assessed. Moreover, hepatitis C virus (HCV) coinfection may be relevant in Mediterranean area, where injecting drug use is a predominant cause Tideglusib of HIV infection [10]. Multiple viral infections may represent an additional confounding factor in homogeneous assays [11], and progressive liver dysfunction may produce abnormal HDL particles which may be a source of inaccuracies in HDL cholesterol measurements. Additionally, the effect of sample storage on serum HDL cholesterol concentration measurements should be assessed because most epidemiological and research studies are performed on samples that have been stored at different temperatures for different periods of time.