Identification of the factors affecting the consistency of DBS formation via experimental design and image processing methodology

Quantification of Zonisamide in Dried Blood Spots and Dried Plasma Spots by UPLC–MS/MS: Application to Clinical Practice

“…Between-run accuracy and precision were estimated by analyzing results obtained from the three single runs over two days for both matrices. Accuracy was reported as a percentage deviation of calculated concentration from the nominal concentration (bias,%) and obtained results were in accordance with the guidance requirements (mean value should be within ±15% of the nominal values for each QC sample, except for the LLOQ which should be within ±20% of the nominal value) [ 9 , 10 , 11 ]. Precision results were expressed as a % Relative Standard Deviation (%RSD) for each level.…”

“…The following sub-headings describe the validation of the developed UPLC–MS/MS method, conducted according to the current FDA [ 9 ], EMA [ 10 ] and ICH M10 guidelines [ 11 ] on bioanalytical method validation with respect to the next aspects: selectivity (endogenous and cross-analyte), LLOQ, calibration curve, accuracy, precision [ 9 , 10 , 11 ], carry-over (instrumentation and spot to spot), matrix effect [ 10 , 11 ] and extraction recovery [ 9 ], dilution integrity [ 9 , 10 , 11 ] and incurred sample analysis [ 9 , 10 , 11 ]. Additionally, matrix spot volume homogeneity and matrix spot homogeneity, as well as the influence of various Hct values on accuracy and precision, were evaluated in accordance with EBF recommendations on DBS assays [ 12 ].…”

“…Furthermore, extraction of the ZNS in the case of the matrix present samples was conducted with 100 µL of blank matrix (blood and plasma) extract, which contained IS in a concentration of 20 ng mL −1 , while the ZNS for the matrix-absent samples was extracted with 100 µL of the extraction solution. According to the recommendations of the EMA guidelines, ZNS, as well as IS matrix factor (MF), were calculated by dividing the peak area of each analyte obtained for the matrix-present sample by the peak area obtained from the matrix-absence sample and expressed as a percentage value [ 10 ]. Additionally, by dividing the MF of the analyte by the MF of the IS, the IS normalized MF was calculated [ 12 ].…”

“…Therefore, the aim of this research was to develop the first UPLC–MS/MS method for the quantification of ZNS in DPSs and dried blood spots (DBSs) with the aid of image processing for precise estimation of DBS and DPS areas after scanning of the Guthrie card on which the appropriate matrix volume was spotted. For the appropriate collection of DBSs, regardless of hematocrit (Hct) value, we applied a previously verified procedure for consistent application of a blood sample volume and formation of spots of the uniform area [ 10 ].…”

Simultaneous Quantification of BCR-ABL and Bruton Tyrosine Kinase Inhibitors in Dried Plasma Spots and Its Application to Clinical Sample Analysis

“…Multiple extraction processes would improve the extraction recovery of some analytes from DPS, thereby improving the consistency of the quantification between both methods. Furthermore, Rmandi c et al 42 reported that blood sample temperature and pipetting technique can contribute to bioanalytical bias in analyses of DBS. These factors could also influence the proportional errors observed in the current results.…”