To the Editor: Carbohydrate-deficient transferrin (CDT; asialo- plus monosialo- plus disialo-[Fe.sub.2]-transferrin) is currently the most specific laboratory marker of chronic alcohol abuse (1, 2). Because of the high prevalence of chronic alcohol abuse in many countries, CDT plays an important role in the areas of employment, traffic safety, and forensic medicine. The potentially strong social impact of an increased CDT value justifies the need for maximally reliable preanalysis, analysis, and interpretation of CDT. There is a highly developed quality-assurance system in toxicologic and forensic drug analysis, including standards and calibration materials, internal quality-control materials, external quality-control programs, and a system of screening and confirmatory analyses (3-5). Although CDT quality-control materials and surveys have become available in recent years and have greatly contributed to the improvement of CDT analysis, an international CDT standard is still lacking. Furthermore, a system for CDT analysis comprising screening and confirmatory analysis, analogous to forensic analysis of cannabinoids, heroin, and cocaine, has not been established. This is surprising because the dependency potential (addictiveness) of ethanol is reported to be comparable to that of cocaine and heroin (6, 7) and much higher than that of cannabis (6, 7). Many state laws regulate medico-legal diagnosis of "acute alcohol abuse", demanding ethanol analysis by two independent analysis methods: an enzymatic NADH method and headspace gas chromatography (8). In contrast to this, the forensic laboratory diagnosis of "chronic alcohol abuse" by measurement of CDT is essentially not regulated and is usually based on only one (immunologic) analytical method. Here we summarize some arguments in favor of confirmatory methods for CDT.
