Citation

Seidl S. Blutalkohol 2004; 41(6): 12-21.

Affiliation

Institut fur Rechtsmedizin, F.-Alexander-Univ. Erlangen-Nurnberg, 91054 Erlangen, Germany

Copyright

(Copyright © 2004, International Committee on Alcohol, Drugs and Traffic Safety and Bund gegen Alkohol und Drogen im Straßenverkehr, Publisher Steintor Verlag)

DOI

unavailable

PMID

unavailable

Abstract

Appraisals for regranting of licenses of DW1 offenders resemble a mosaic, consisting of different medical and psychological examination methods. In order to detect an ongoing alcohol misuse or to verify an alleged teetotalism, the medical examination routinely comprises the measurement of the alcohol markers GGT and MCV, sometimes supplemented by CDT. Due to the low positive predictive value and specificity of GGT, the quantification of the differentiation markers AST and ALT is inevitable to ascertain an alcohol misuse. Additionally, AST/ALT and GGT/AST ratios >2 suggest a hepatopathy caused by ethanol. The diagnostic specificity for an ethanol misuse of MCV is a little higher than of GGT. Nevertheless, a complete blood count is necessary to exclude a macrocytic anemia or other hematological diseases that may come along with macrocytosis. The time frame of MCV complies with the lifespan of erythrocytes and averages out 120 days. Therefore, short-term changes of drinking behavior are not recorded by this marker. Carbohydrate Deficient Transferrin (CDT) possesses a high specificity for alcohol misuse, but needs a special drinking pattern with a daily consume of 50 to 80 gram ethanol. For forensic purposes, an upper reference value of 3.3% is suggested at use of the new %CDT immunoassay of Axis-Shield (Oslo, Norway). The appraiser has to ensure that an artificial elevation of the CDT value (for example by storage of the blood sample at room temperature during the transport to the laboratory) can be excluded. Due to the low negative predictive value of CDT, CDT concentrations less than 3.3% are not qualified to reinforce an alleged teetotalism. This, however, can be achieved by ethyl glucuronide, a direct ethanol metabolite with a specificity for recent alcohol consumption of 100%, which one can still find several hours after the end of alcohol consumption in blood and up to 80 hours in urine, depending on the initial concentration. As the expert has to bargain for drinking pauses an the occasion of the appraisal, he has to take notice of the time spans that different markers need for normalization. The question and the circumstances of the individual case specify the selection of the markers and their interpretation. The combination of two or more alcohol markers may lead to a extensive reduction of specificity, if the exceeding of the reference value by just one marker is considered to be sufficient to diagnose an alcohol misuse. A substantial reduction of sensitivity was the result, however, if the appraiser would claim that all markers have to exceed their reference spans to enable him to diagnose an alcohol misuse.