Hemato-Critical Issues in Quantitative Analysis of Dried Blood Spots: Challenges and Solutions

“…This partial-spot approach requires the assessment of the impact of variables such as hematocrit, punch localization and spot volume on the quantitative result [27,28].…”

Section: Introductionmentioning

confidence: 99%

Quantification of phosphatidylethanol 16:0/18:1, 18:1/18:1, and 16:0/16:0 in venous blood and venous and capillary dried blood spots from patients in alcohol withdrawal and control volunteers

et al. 2015

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“…Hct and blood volume had a considerable impact on the concentrations of caffeine and paraxanthine, similar to that described for several other small molecules [32][33][34][35]. The range in which the impact of Hct was evaluated, 0.20 -0.60, was considered to be relevant and sufficient, as it covers approximately 99.5% of a hospital population (including both 'normal' and 'critically ill' patients) [10]. The 7.5 -50 µL volume range was chosen to represent typical spot sizes resulting from a single drop of blood.…”

Section: Discussionmentioning

confidence: 91%

“…From an analytical perspective, the (combined) influence of hematocrit (Hct), blood volume spotted and punch localization on a DBS result are important challenges to be addressed during method development and validation [2,3,[10][11][12]. The degree of bias caused by these parameters needs to be evaluated on a case-by-case basis since it may be influenced by several factors, such as compound characteristics, filter paper type or extraction conditions.…”

Section: Introductionmentioning

confidence: 99%

Why Dried Blood Spots Are an Ideal Tool for CYP1A2 Phenotyping

2014

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Background and ObjectiveDried blood spot (DBS) sampling has gained wide interest in bioanalysis during the last decade. Also in pharmacokinetic and phenotyping studies, DBS-based sampling has already been successfully applied. However, all available phenotyping studies used small data sets and did not include a systematic evaluation of DBS-specific parameters. The latter is important since several of these factors still challenge the breakthrough of DBS in routine practice. In this study, caffeine and paraxanthine are determined in capillary DBS, venous DBS, whole blood and plasma for CYP1A2 phenotyping (CYP; cytochrome P450). The aim of this study was to explore the usefulness of DBS as a tool for CYP1A2 phenotyping. MethodsA CYP1A2 phenotyping study was conducted in seventy-three healthy volunteers, who received a 150 mg oral dose of caffeine. Six hours post-administration, caffeine and paraxanthine concentrations and paraxanthine:caffeine molar concentration ratios, i.e. the actual CYP1A2 phenotyping indices, were determined in capillary DBS (obtained by non-volumetric application, direct from the fingertip), venous DBS, whole blood and plasma. Furthermore, the impact of DBS-specific parameters, including hematocrit, volume spotted and punch location, was evaluated. ResultsConcentrations of caffeine and paraxanthine in capillary DBS were on average 12.7 respectively 13.8 % lower than those in venous DBS and 31.5 respectively 33.1 % lower than those in plasma. While these differences were statistically significant (p < 0.001), no significant difference was observed between the paraxanthine:caffeine molar ratios in the distinct evaluated matrices (p ≥ 0.053). This ratio also alleviated the impact of hematocrit and volume spotted. ConclusionsUsing the largest DBS-based phenotyping study to date, we have demonstrated that CYP1A2 phenotyping in capillary DBS is a valid and convenient alternative for the classical plasma-based approach. Additionally, we have provided an objective basis as to why DBS are an ideal tool for CYP1A2 phenotyping.  While capillary DBS concentrations of caffeine and paraxanthine differed significantly from those in venous blood and plasma and were impacted by hematocrit and blood volume spotted, the paraxanthine:caffeine molar ratio essentially remained unaffected. Capillary DBS-based CYP1A2 phenotyping proved to be a valid and convenient alternative for the classical plasma-based approach.4

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“…These parameters are the impact of the volume of blood spotted onto the filter paper, the punch localization and, undoubtedly the most discussed issue in DBS analysis, the influence of hematocrit. The latter problem, along with strategies to cope with it, has been reviewed recently by De Kesel et al [35].…”

Section: Dried Blood Spotsmentioning

confidence: 99%

Alternative Sampling Strategies for Cytochrome P450 Phenotyping

2015

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Interindividual variability in the expression and function of drug metabolizing cytochrome P (CYP) 450 enzymes, determined by a combination of genetic, non-genetic and environmental parameters, is a major source of variable drug response. Phenotyping by administration of a selective enzyme substrate, followed by the determination of a specific phenotyping metric, is an appropriate approach to assess the in vivo activity of CYP450 enzymes, as it takes into account all influencing factors. A phenotyping protocol should be as simple and convenient as possible. Typically, phenotyping metrics are determined in traditional matrices, such as blood, plasma or urine. Several sampling strategies have been proposed as an alternative for these traditional sampling techniques.In this review, we provide a comprehensive overview of available methods using dried blood spots, hair, oral fluid, exhaled breath and sweat for in vivo CYP450 phenotyping. We discuss the relation between phenotyping metrics measured in these samples and those in conventional matrices, along with the advantages and limitations of the alternative sampling techniques. Reliable phenotyping procedures for several clinically relevant CYP450 enzymes, including CYP1A2, CYP2C19 and CYP2D6, are currently available for oral fluid, breath or dried blood spots, while additional studies are needed for other CYP450 isoforms, such as CYP3A4. The role of hair analysis for this purpose remains to be established. Being non-or minimally invasive, these sampling strategies provide convenient and patient-friendly alternatives for classical phenotyping procedures, which may contribute to the implementation of CYP450 phenotyping in clinical practice. 4 Key Points Phenotyping by administration of a selective probe drug, followed by determination of a specific phenotyping metric, allows to assess the in vivo enzyme activity of CYP450 enzymes, taking into account genetic, non-genetic and environmental influencing factors. In addition to classical sampling techniques, such as blood or urine collection, reliable phenotyping procedures for several clinically relevant CYP450 enzymes are currently available for oral fluid, breath and dried blood spots.

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Hemato-Critical Issues in Quantitative Analysis of Dried Blood Spots: Challenges and Solutions

Cited by 228 publications

References 108 publications

Quantification of phosphatidylethanol 16:0/18:1, 18:1/18:1, and 16:0/16:0 in venous blood and venous and capillary dried blood spots from patients in alcohol withdrawal and control volunteers

Quantification of phosphatidylethanol 16:0/18:1, 18:1/18:1, and 16:0/16:0 in venous blood and venous and capillary dried blood spots from patients in alcohol withdrawal and control volunteers

Why Dried Blood Spots Are an Ideal Tool for CYP1A2 Phenotyping

Alternative Sampling Strategies for Cytochrome P450 Phenotyping

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