Radioimmunoassay screening of dried blood spot materials for benzoylecgonine

Dried matrix spots in forensic toxicology

Dried matrix spots (DMS) has gained the attention of different professionals in different fields, including toxicology. Investigations have been carried out in order to assess the potential of using DMS for the analysis of illicit substances, the main interest of forensic toxicologists. This technique uses minimal volumes of samples and solvents, resulting in simple and rapid extraction procedures. Furthermore, it has proved to increase analyte stability, improving storage and transportation. However, DMS presents some limitations: the hematocrit influencing accuracy and inconsistencies regarding the means of spotting samples and adding internal standard on paper. Thus, we provide an overview of analytical methodologies with forensic applications focusing on drugs of abuse and discussing the main particularities, limitations and achievements.

An LC-MS/MS method for comparing the stability of ethanol's non-oxidative metabolites in dried blood spots during 90 days

Problems of stability were found for biomarkers of alcohol consumption: ethyl glucuronide (EtG), ethyl sulfate (EtS), phosphatidylethanols (PEths), and fatty acid ethyl esters (FAEEs) in whole blood. The purpose of this study was to establish a method for the determination of these four kinds of ethanol's non-oxidative metabolites in dried blood spots (DBS) by liquid chromatography tandem mass spectrometry (LC-MS/MS), and to evaluate their stability. In this method, 50 μL of human blood was spotted onto a filter paper for DBS analysis. Samples were extracted by methanol, reconstituted by 2-propanol, and injected into the LC-MS/MS system. Limits of detection were among 0.5-50 ng/mL, and deviations in accuracy and precision were all lower than 15% at three quality control levels. The stability of the four kinds of ethanol non-oxidative metabolites in DBS was investigated during a 90-day range under three temperatures, -20 °C, 4 °C, and 25 °C. EtG and EtS showed a high level of stability in DBS in the 90-day range, regardless of the temperature. FAEEs were unstable after three days. PEths showed stability within 15 days in postmortem DBS and 60 days in antemortem DBS, respectively, at all temperatures.

Innovations in health and demographic surveillance systems to establish the causal impacts of HIV policies

PURPOSE OF REVIEW

Health and demographic surveillance systems (HDSS), in conjunction with HIV treatment cohorts, have made important contributions to our understanding of the impact of HIV treatment and treatment-related interventions in sub-Saharan Africa. The purpose of this review is to describe and discuss innovations in data collection and data linkage that will create new opportunities to establish the impacts of HIV treatment, as well as policies affecting the treatment cascade, on population health and economic and social outcomes.

RECENT FINDINGS

Novel approaches to routine collection of biomarkers, behavioural data, spatial data, social network information, migration events and mobile phone records can significantly strengthen the potential of HDSS to generate exposure and outcome data for causal analysis of HIV treatment impact and policies affecting the HIV treatment cascade. Additionally, by linking HDSS data to health service administration, education and welfare service records, researchers can substantially broaden opportunities to establish how HIV treatment affects health and economic outcomes when delivered through public sector health systems and at scale.

SUMMARY

As the HIV treatment scaleup in sub-Saharan Africa enters its second decade, it is becoming increasingly important to understand the long-term causal impacts of large-scale HIV treatment and related policies on broader population health outcomes, such as noncommunicable diseases, as well as on economic and social outcomes, such as family welfare and children's educational attainment. By collecting novel data and linking existing data to public sector records, HDSS can create near-unique opportunities to contribute to this research agenda.

Cocaine and metabolite concentrations in DBS and venous blood after controlled intravenous cocaine administration

BACKGROUND

DBS are an increasingly common clinical matrix.

METHODS & RESULTS

Sensitive and specific methods for DBS and venous blood cocaine and metabolite detection by LC-HRMS and 2D GC-MS, respectively, were validated to examine correlation between concentrations following controlled intravenous cocaine administration. Linear ranges from 1 to 200 µg/l were achieved, with acceptable bias and imprecision. Authentic matched specimens' (392 DBS, 97 venous blood) cocaine and benzoylecgonine concentrations were qualitatively similar, but DBS had much greater variability (21.4-105.9 %CV) and were lower than in blood.

CONCLUSION

DBS offer advantages for monitoring cocaine intake; however, differences between capillary and venous blood and DBS concentration variability must be addressed.

Spot them in the spot: analysis of abused substances using dried blood spots

Dried blood spot (DBS) sampling and DBS analysis have increasingly received attention during recent years. Furthermore, a substantial number of DBS methods has recently become available in clinical, forensic and occupational toxicology. In this review, we provide an overview of the different DBS-based methods that have been developed for detecting (markers of) abused substances. These include both legal and illegal drugs belonging to different categories, including cannabinoids, cocaine and metabolites, opioids, benzodiazepines and Z-drugs, amphetamines and analogs, gamma-hydroxybutyric acid, ketamine and novel psychoactive substances such as cathinones. Markers of ethanol consumption and tobacco use are also covered in this review. Since the majority of published methods has shown promising results overall, an interesting role for DBS analysis in diverse toxicological applications can be envisaged. For the distinct applications, we discuss the specific potential and benefits of DBS, the associated limitations and challenges, as well as recent developments and future perspectives.

Current and future use of "dried blood spot" analyses in clinical chemistry

The analysis of blood spotted and dried on a matrix (i.e., "dried blood spot" or DBS) has been used since the 1960s in clinical chemistry; mostly for neonatal screening. Since then, many clinical analytes, including nucleic acids, small molecules and lipids, have been successfully measured using DBS. Although this pre-analytical approach represents an interesting alternative to classical venous blood sampling, its routine use is limited. Here, we review the application of DBS technology in clinical chemistry, and evaluate its future role supported by new analytical methods such as mass spectrometry.

Simultaneous screening and detection of drugs in small blood samples and bloodstains

A gas chromatography-mass spectrometry (GC-MS) method is described for the screening and detection of morphine, codeine, cocaine, benzoylecgonine, methylecgonine, cocaethylene, delta-9-tetrahydrocannabinol (THC), 11-nor-9-carboxy-THC (THC-COOH), 11-hydroxy-THC (11-OH-THC), amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymetamphetamine (MDMA) and N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB) in small blood samples and bloodstains using solid phase SPE columns and a pipetting robot (Gilson Aspec XL). The detection limits are in the order of 1.62-4.10 ng/50 microl spot (amphetamines), 0.15-0.82 ng/50 microl spot (cannabinoids), 1.67-4.70 ng/50 microl spot (cocaine and derivatives) and 4.53-4.91 ng/50 microl spot (opiates) and the correlation factors are between 0.9957 and 0.9999. The method has proven useful in forensic cases with only small sample volumes or bloodstains.

Determination of drugs of abuse in blood

The detection and quantitation of drugs of abuse in blood is of growing interest in forensic and clinical toxicology. With the development of highly sensitive chromatographic methods, such as high-performance liquid chromatography (HPLC) with sensitive detectors and gas chromatography-mass spectrometry (GC-MS), more and more substances can be determined in blood. This review includes methods for the determination of the most commonly occurring illicit drugs and their metabolites, which are important for the assessment of drug abuse: Methamphetamine, amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), N-ethyl-3,4-methylenedioxyamphetamine (MDEA), 3,4-methylenedioxy-amphetamine (MDA), cannabinoids (delta-9-tetrahydrocannabinol, 11-hydroxy-delta-9-tetrahydrocannabinol, 11-nor-9-carboxy-delta-9-tetrahydrocannabinol), cocaine, benzoylecgonine, ecgonine methyl ester, cocaethylene and the opiates (heroin, 6-monoacetylmorphine, morphine, codeine and dihydrocodeine). A number of drugs/drug metabolites that are structurally close to these substances are included in the tables. Basic information about the biosample assayed, work-up, GC column or LC column and mobile phase, detection mode, reference data and validation data of each procedure is summarized in the tables. Examples of typical applications are presented.

An evaluation of the use of dried blood spots from newborn screening for monitoring the prevalence of cocaine use among childbearing women

A collaborative March of Dimes study was designed to examine the utility of dried blood spot (DBS) materials routinely collected from newborns as a source for monitoring cocaine exposure and to assess the prevalence of cocaine use among childbearing women in Georgia. We used a modified urinary radioimmunoassay (RIA) to anonymously detect the cocaine metabolite benzoylecgonine (BE) in DBSs. Extensive efforts were undertaken to assure absolute nonlinkage of BE data to any individual. The positive results found by RIA were confirmed by a mass spectrometry (MS) method specifically developed to detect BE in DBSs. BE was measured in 23,141 DBSs collected during 2 months of routine newborn screening in Georgia. A good correlation was observed for RIA results versus MS results (r2 = 0.97). The estimated minimal statewide BE prevalence was 4.8 per 1000 childbearing women. We demonstrated that immunoassay testing for cocaine without confirmatory testing can yield falsely elevated prevalence rates. When proper confirmatory testing is done, DBSs are a valuable source for population-based monitoring of substance abuse among childbearing women.

Preliminary investigation of the use of dried-blood spots for the assessment of in utero exposure to environmental pollutants

We determined the concentration of dichlorodiphenyldichloroethylene (p,p'-DDE) in dried-blood spot specimens from 2-day-old infants from rural Texas who had never been breast fed. Anonymous, residual whole blood spots on filter paper, previously used for routine newborn screening procedures, were soaked in a phosphate buffer, extracted with an organic solvent, and eluted through silica gel. The concentrated eluates were analyzed by capillary gas chromatography with electron capture detection (ECD). The blood collected from 10 newborns was analyzed and found to contain DDE concentrations ranging from 0.13 to 1.87 pg/microliter with a mean of 0.72 pg/microliter. One of the 10 newborns had a whole blood DDE concentration of 1.87 pg/microliter, which was greater than the concentration of 1.34 pg/microliter in a freshly drawn sample from an adult donor whose blood serum was shown to contain DDE. With improvement in detection limits, this approach has the potential to displace the analyses of mothers' blood (as a surrogate indicator of infants' exposures) and cord blood as standard procedures for determining the newborns' body burden of environmental pollutants.