No abstract

Alcohol abuse is a common problem in society; however, the technical capabilities of evaluating individual alcohol consumption using objective biomarkers are rather limited at present. In recent years research has focused on alcohol markers using hair analysis but data on performance and reliable cut-off values are still lacking. In this study 169 candidates were tested to compare traditional biomarkers, such as carbohydrate-deficient-transferrin (CDT), gamma glutamyl transferase (GGT), aspartate amino transferase, alanine amino transferase and the mean corpuscular volume of the erythrocytes, with alcohol markers detectable in hair such as ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs). This study revealed that EtG, GGT and CDT showed the best results, demonstrating areas under the curve calculated from receiver operating characteristics of 0.941, 0.943 and 0.899 respectively. The lowest false-negative and false-positive rates were obtained by using a combined interpretation system for hair EtG and FAEEs. All markers demonstrated only low to moderate correlations. Optimum cut-off values for differentiation between social and chronic excessive drinking calculated for hair EtG and FAEEs were 28 pg/mg and 0.675 ng/mg, respectively. The critical values published in the "Consensus on Alcohol Markers 2012" by the Society of Hair Testing were confirmed.

In cases where the amount of hair available is not sufficient for a general unknown screening for drugs, nails appear to be a useful comparable matrix for the detection of long-term drug consumption due to the comparison of the qualitative GUS results from the hair and nail samples in this study.

Nail samples may serve as an alternative matrix for the detection of long-term consumption of a wide range of drugs. Based on our results, drug concentrations in nails are not comparable to those in hair. The main mechanisms for drug incorporation into the nails may be during the formation of the nail plate by the germinal matrix. However, external contamination can also affect the analysis of nail clippings.