Recoveries of Phenylalanine from Two Sets of Dried-Blood-Spot Reference Materials: Prediction from Hematocrit, Spot Volume, and Paper Matrix

Adam, Barbara W.; Alexander, J. Richard; Sj, Smith; Chace, Donald H.; Loeber, J.G.; Elvers, L.H.; Hannon, W. Harry

doi:10.1093/clinchem/46.1.126

Cited by 124 publications

(33 citation statements)

References 5 publications

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“…Chromatographic effect was investigated to determine whether the fibers in the filter paper matrix influence the spread of blood across the spot when the blood is applied in a single application to the center of the printed circle (Adam et al ., ). Absorbent cards were not suitable for use as the large molecular weight and polarity of the TAC molecule would result in it being distributed unevenly throughout the blood spot, thus introducing a potentially significant source of measurement error (Webb et al ., ).…”

Section: Resultsmentioning

confidence: 97%

“…Samples should be discarded if contamination or hemolysis was indicated. As the volume of blood contained in a 3 mm diameter blood spot equals ~3.1–3.2 μL (Adam et al ., ), one of the most difficult parts of the method development was achieving a high and reproducible recovery from the sampling paper. The two‐step sample preparation (solvent extraction in ultrasonication and liquid–liquid extraction) was necessary to obtain a pre‐set LLOQ of 1 ng/mL of TAC from DBS.…”

Section: Resultsmentioning

confidence: 99%

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Development and validation of a sensitive LC‐MS/MS method for determination of tacrolimus on dried blood spots

Cao

Huang

et al. 2012

Biomedical Chromatography

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A bioanalytical method for the quantification of tacrolimus (TAC) on dried blood spots (DBS) using liquid chromatography, electrospray ionization coupled with tandem mass spectrometry (LC-ESI-MS/MS) was developed and validated. It involves solvent extraction of a punch disk of DBS followed by liquid-liquid extraction. The analyte and the internal standard (IS, ascomycin) were separated on a phenyl column using an isocratic mobile phase elution at a flow rate of 0.3 mL/min. The assay was linear from 1 to 80 ng/mL. The mean recovery of TAC was 76.6%. Intra-assay, inter-assay imprecision and biases were all less than 15%. TAC on DBS was stable for at least 10 days at room temperature, and at least 24 h at 50°C. A chromatographic effect of the filter paper (Whatman 903) was not detected. The volume of blood (15-50 μL) and hematocrit of blood (ranging from 23.2 to 48.6%) did not show a significant influence on detection of TAC concentration by DBS-LC-MS/MS. Fifty samples from patients were detected by both DBS-LC-MS/MS and microparticle enzyme-linked immunoassay (MEIA). TAC concentrations measured by DBS-LC-MS/MS method tended to be lower than those by MEIA.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Development and validation of a sensitive LC‐MS/MS method for determination of tacrolimus on dried blood spots

Cao

Huang

et al. 2012

Biomedical Chromatography

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“…The hematocrit value (the proportion of blood volume occupied by red blood cells) is an important factor in DBS analysis, and has a high impact on the size of the blood spot on filter paper. At high hematocrit levels, owing to the increase in the number of blood cells, the viscosity of blood increases and subsequently leads to small spots on the card (Denniff and Spooner, 2010;Adam et al, 2000;Holub et al, 2006). In the case of low hematocrit values the sizes of the spots are larger owing to lower number of blood cells and lower viscosity.…”

Section: Methods Developmentmentioning

confidence: 99%

Exploring dried blood spot sampling technique for simultaneous quantification of antiretrovirals: lamivudine, stavudine and nevirapine in a rodent pharmacokinetic study

Nirogi

Kandikere

Komarneni

et al. 2012

Biomedical Chromatography

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A high-performance liquid chromatography/positive ion electrospray tandem mass spectrometry method for the simultaneous quantification of lamivudine, stavudine and nevirapine was developed and validated in dried blood spot (DBS) cards. The analytes were separated using an isocratic mobile phase on a reverse phase column and analyzed by MS/MS in the MRM mode using the respective [M + H]⁺ ions, m/z 230-112 for lamivudine, m/z 225-127 for stavudine, m/z 267-226 for nevirapine, m/z 383-337 for zidovudine (IS). The lower limit of quantification was 1 ng/mL for both lamivudine and stavudine and 10 ng/mL for nevirapine. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. The method was successfully applied to quantify them in a rat pharmacokinetic study in whole blood, plasma and DBS cards after a single oral co-administration at the dose of 10, 2 and 13 mg/kg for lamivudine, stavudine and nevirapine, respectively, to male Wistar rats. Following oral administration the pharmacokinetic results in all the matrices are in close agreement. Thus accomplishment of this method would facilitate the ease of collection of clinical samples on DBS cards for lamivudine, stavudine and nevirapine during human clinical trials and therapeutic drug monitoring.

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“…The influence of blood spot volume is still controversial, for example, using phenylalanine Adam and colleagues (2000) found that lower concentrations of analyte were measured in DBS samples prepared using a lower volume of blood. 21 While others did not find a significant effect of blood spot volume on the concentration of the analyte(s) measured. 16 It is recommended, however, that such relationships are checked for analytes of interest when using the "direct spotting" method.…”

Section: Influence Of Volume Of Bloodmentioning

confidence: 98%

Hematocrit, blood volume, and surface area of dried blood spots – a quantitative model

Alsous

Hawwa

McElnay

2020

Drug Testing and Analysis

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The use of the dried blood spot (DBS) sampling technique has extended the scope of clinical research, particularly in children. The effects of different hematocrit levels (25–55%) and different blood volumes (7.5–30 μL) on the surface area of the blood spots were investigated using ImageJ® software. Variation in hematocrit levels between patients and inaccuracies in blood volumes applied to Guthrie cards can have a marked effect on analyte concentrations measured in DBS samples. The current study presents a validated model that links blood volume and hematocrit to the surface area of the blood spot. The final model showed that both factors affect the blood spot surface area, however, the positive effect of blood volume is higher than the negative effect of hematocrit. The measurement of surface area could be added as an additional quality control step in clinical studies that have adopted fixed volume DBS sampling for the quantification of the analytes. This approach can be used in estimating the hematocrit if this is not known for a patient or estimating the volume in spots that are visually different in size from the norm, i.e. technical error.

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Recoveries of Phenylalanine from Two Sets of Dried-Blood-Spot Reference Materials: Prediction from Hematocrit, Spot Volume, and Paper Matrix

Cited by 124 publications

References 5 publications

Development and validation of a sensitive LC‐MS/MS method for determination of tacrolimus on dried blood spots

Development and validation of a sensitive LC‐MS/MS method for determination of tacrolimus on dried blood spots

Exploring dried blood spot sampling technique for simultaneous quantification of antiretrovirals: lamivudine, stavudine and nevirapine in a rodent pharmacokinetic study

Hematocrit, blood volume, and surface area of dried blood spots – a quantitative model

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