TY - JOUR
T1 - Evaluation of an immunoassay for determination of plasma efavirenz concentrations in resource-limited settings
AU - Abdissa, Alemseged
AU - Wiesner, Lubbe
AU - McIlleron, Helen
AU - Friis, Henrik
AU - Andersen, Åse Bengård
AU - Kæstel, Pernille
N1 - CURIS 2014 NEXS 205
PY - 2014/6/5
Y1 - 2014/6/5
N2 - Introduction: Therapeutic drug monitoring (TDM) may improve antiretroviral efficacy through adjustment of individual drug administration. This could result in reduced toxicity, prevent drug resistance, and aid management of drug-drug interactions. However, most measurement methods are too costly to be implemented in resource-limited settings. This study evaluated a commercially available immunoassay for measurement of plasma efavirenz. Methods: The immunoassay-based method was applied to measure efavirenz using a readily available Humastar 80 chemistry analyzer. We compared plasma efavirenz concentrations measured by the immunoassay with liquid chromatography tandem mass spectrometry (LC-MS/MS) (reference method) in 315 plasma samples collected from HIV patients on treatment. Concentrations were categorized as suboptimal <1 μg/ml, normal 1-4 μg/ml or high >4 μg/ml. Agreement between results of the methods was assessed via Bland-Altman plot and k statistic values. Results: The median Interquartile range (IQR) efavirenz concentration was 2.8 (1.9; 4.5) mg/ml measured by the LC-MS/MS method and 2.5 (1.8; 3.9) μg/ml by the immunoassay and the results were well correlated (ρ =0.94). The limits of agreement assessed by Bland-Altman plots were - 2.54; 1.70 μg/ml. Although immunoassay underestimated high concentrations, it had good agreement for classification into low, normal or high concentrations (K = 0.74). Conclusions: The immunoassay is a feasible alternative to determine efavirenz in areas with limited resources. The assay provides a reasonable approximation of efavirenz concentration in the majority of samples with a tendency to underestimate high concentrations. Agreement between tests evaluated in this study was clinically satisfactory for identification of low, normal and high efavirenz concentrations.
AB - Introduction: Therapeutic drug monitoring (TDM) may improve antiretroviral efficacy through adjustment of individual drug administration. This could result in reduced toxicity, prevent drug resistance, and aid management of drug-drug interactions. However, most measurement methods are too costly to be implemented in resource-limited settings. This study evaluated a commercially available immunoassay for measurement of plasma efavirenz. Methods: The immunoassay-based method was applied to measure efavirenz using a readily available Humastar 80 chemistry analyzer. We compared plasma efavirenz concentrations measured by the immunoassay with liquid chromatography tandem mass spectrometry (LC-MS/MS) (reference method) in 315 plasma samples collected from HIV patients on treatment. Concentrations were categorized as suboptimal <1 μg/ml, normal 1-4 μg/ml or high >4 μg/ml. Agreement between results of the methods was assessed via Bland-Altman plot and k statistic values. Results: The median Interquartile range (IQR) efavirenz concentration was 2.8 (1.9; 4.5) mg/ml measured by the LC-MS/MS method and 2.5 (1.8; 3.9) μg/ml by the immunoassay and the results were well correlated (ρ =0.94). The limits of agreement assessed by Bland-Altman plots were - 2.54; 1.70 μg/ml. Although immunoassay underestimated high concentrations, it had good agreement for classification into low, normal or high concentrations (K = 0.74). Conclusions: The immunoassay is a feasible alternative to determine efavirenz in areas with limited resources. The assay provides a reasonable approximation of efavirenz concentration in the majority of samples with a tendency to underestimate high concentrations. Agreement between tests evaluated in this study was clinically satisfactory for identification of low, normal and high efavirenz concentrations.
U2 - 10.7448/IAS.17.1.18979
DO - 10.7448/IAS.17.1.18979
M3 - Journal article
C2 - 24909561
SN - 1758-2652
VL - 17
JO - International AIDS Society. Journal
JF - International AIDS Society. Journal
M1 - 18979
ER -
