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Background: Atovaquone has traditionally been used as an antiparasitic and antifungal agent, but recent studies have shown its potential as an anticancer agent. The high variability in atovaquone bioavailability highlights the need for therapeutic drug monitoring, especially in pediatric patients. The goal of our study was to develop and validate the performance of an assay to quantify atovaquone plasma concentrations collected from pediatric cancer patients using LC-MS/MS. Methods: Atovaquone was extracted from a 10 µL volume of K2-EDTA human plasma using a solution consisting of ACN: EtOH: DMF (8:1:1 v:v:v), separated using reverse-phase chromatography, and detected using a SCIEX 5500 QTrap MS system. LC-MS/MS assay performance was evaluated for precision, accuracy, carryover, sensitivity, specificity, linearity, and interferences. Results: Atovaquone and its deuterated internal standard were analyzed using a gradient chromatographic method that had an overall cycle-time of 7.4 min per injection, and retention times of 4.3 min. Atovaquone was measured over a dynamic concentration range of 0.63 - 80 µM with a deviation within ≤ ± 5.1 % of the target value. Intra- and inter-assay precision were ≤ 2.7 % and ≤ 8.4 %, respectively. Dilutional, carryover, and interference studies were also within acceptable limits. Conclusions: Our studies have shown that our LC-MS/MS-based method is both reliable and robust for the quantification of plasma atovaquone concentrations and can be used to determine the effective dose of atovaquone for pediatric patients treated for AML.
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Introduction: Quantitation of the isomeric branched-chain amino acids (BCAA; valine, alloisoleucine, isoleucine, leucine) is a challenging task that typically requires derivatization steps or long runtimes if a traditional chromatographic method involving a ninhydrin ion pairing reagent is used. Objectives: To develop and perform clinical validation of a rapid, LC-MS/MS-based targeted metabolomics assay for detection and monitoring of underivatized BCAA in human plasma. Methods: Various columns and modes of chromatography were tested. The final optimized method utilized mixed mode chromatography with an Intrada column under isocratic condition. Sample preparation utilized the 96-well format. Briefly, extraction solvent containing the internal standard is added to 20 uL of sample, followed by shaking and positive pressure filtering, and the resulting extracted sample is analyzed. The assay was validated based on accepted quality standards (e.g., CLIA and CLSI) for clinical assays. Results: The method is linear over a wide range of concentrations, 2.0-1500 µM, with LOD of 0.60 µM and LOQ of 2.0 µM. The precision of the assay was 4-10% across analytes. The method was also validated against reference laboratories via blinded split-sample analysis and demonstrated good agreement with accuracy: 89-95% relative to the external group mean. Conclusion: We have developed a method that is accurate, rapid, and reliable for routine clinical testing of patient sample BCAA, which is used in the diagnosis and management of maple syrup urine disease (MSUD). The assay also has desirable characteristics, such as short run time, small sample volume requirement, simple sample preparation without the need for derivatization, and high throughput.
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Objective To investigate the necessity of dilution in samples with high concentrations of D-Dimer and optimum dilution multiple.Methods Quality control products and calibration were detected by using Sysmex CS5100 for precision evaluation,including within-batch and between-run precision.Calibration were detected for validation of linear range and clinical reportable.Samples with D-Dimer5 mg/L and FDP>20 μg/mL were also serially diluted and detected to calculated recovery rate.Results Within-batch and between-run coefficients of variation were both less than 3%.Within the scope of 0.207-5.170 mg/L,the linear distribution was fine.The clinical reportable range was 0.207-165.440 mg/L.For samples with D-Dimer5 mg/L and FDP>20 μg/mL,there was obvious antigen excess phenomenon,and gradient dilution was required.Conclusion For samples with D-Dimer>5 mg/L and FDP>20 μg/mL,dilution should be performed to ensure the accuracy of detected results.
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Objective To establish detection limit and clinical reportable range for detection of anti-HBs by chemiluminescence method and evaluate by clinical application.Methods Referring to the Clinical and Laboratory Standards Institute (CLSI) relevant documents,the programme of blank limit (LoB),detection limit (LoD),quantitative detection limit (LoQ),analytical range of measurement (AMR),clinical reportable range (CRR) for detection of anti-HBs by chemiluminescence method,were designed and measured.The established clinical reportable range and maximum dilution were used to predict the recovery stage of acute hepatitis B patients and to evaluate the effectiveness of different vaccines.Results LoB,LoD,LoQ,AMR and CRR for detection of anti-HBs by chemiluminescence method were 0.87,1.89,3.0,0～970.50 and 3.0 ～48 525 mIU/ml respectively,and the maximum dilution was 1 ∶ 50.The patient with acute hepatitis B showed elevated anti-HBs at fourth weeks after treatment (CRR).The anti-HBs mean was the highest in the B vaccine of the three vaccines.Conclusion The establishment of detection limit and clinical reportable range for detection of anti-HBs by chemiluminescence method was better meet the requirements of clinical laboratories,provide reliable results for clinical laboratories.
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OBJECTIVES: Body fluid specimens other than serum, plasma or urine are generally not validated by manufacturers, but analysis of these non-standard fluids can be important for clinical diagnosis and management. Laboratories, therefore, rely on the published literature to better understand the validation and implementation of such tests. This study utilized a data-driven approach to determine the clinical reportable range for 11 analytes, evaluated a total bilirubin assay, and assessed interferences from hemolysis, icterus, and lipemia in non-standard fluids. DESIGN AND METHODS: Historical measurements in non-standard body fluids run on a Beckman Coulter DxC800 were used to optimize population-specific clinical reportable ranges for albumin, amylase, creatinine, glucose, lactate dehydrogenase, lipase, total bilirubin, total cholesterol, total protein, triglyceride and urea nitrogen run on the Beckman Coulter AU680. For these 11 analytes, interference studies were performed by spiking hemolysate, bilirubin, or Intralipid® into abnormal serous fluids. Precision, accuracy, linearity, and stability of total bilirubin in non-standard fluids was evaluated on the Beckman Coulter AU680 analyzer. RESULTS: The historical non-standard fluid results indicated that in order to report a numeric result, 4 assays required no dilution, 5 assays required onboard dilutions and 2 assays required both onboard and manual dilutions. The AU680 total bilirubin assay is suitable for clinical testing of non-standard fluids. Interference studies revealed that of the 11 total AU680 analyte measurements on non-standard fluids, lipemia affected 1, icterus affected 3, and hemolysis affected 5. CONCLUSIONS: Chemistry analytes measured on the AU680 demonstrate acceptable analytical performance for non-standard fluids. Common endogenous interference from lipemia, icterus, and hemolysis (LIH) are observed and flagging rules based on LIH indices were developed to help improve the clinical interpretation of results.
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Objective To evaluate the detection performance of the cobas8000 c702 fully automatic biochemical analyzer for de‐tecting the second generation Roche urine trace albumin (ALBU2) .Methods (1) The precise evaluation :with the allowable error stipulated by CLIA 88 as the basis ,the requirements were the repeat precision <1/4TEa ,and intermediate precision <1/3TEa;(2) the linear range and the evaluation of the reportable range :the EP6‐A scheme was adopted ,and extend to calculate the average re‐covery rate of dilution ,the clinical reportable range was evaluated by the average dilution recovery of 90% -110% ;(3) the carry o‐ver pollution assessment :the carry over pollution of serum albumin on urine trace albumin detection was evaluated by the judgment standard of carry over pollution rate of 0 .5% ;(4)the methodological comparative analysis :with SIEMENS BN Ⅱas the reference system ,the Roche Cobas 8000 C702 and the BN2 results were performed the correlation contrastive analysis .Results The repeat precision :low concentration CV=1 .98% .high concentration CV=1 .64% ;intermediate precision :low concentration CV=4 .35% , high concentration CV=1 .20% ;the linear range verification :the measurement range 5 .6-413 .55 mg/L ;clinical reportable range :in the maximum diluted multiples of 30 times ,the clinical reportable range was 5 .6-12 406 .5 mg/L ;the carry over pollution rate :serum albumin (42 .6 g/L) on urine trace albumin(6 .9 mg/L) ,the carry over pollution rate was 0 .28% ;the indoor comparison :in the concentration within 200 mg/L ,the regression line was Y=0 .896 X+5 .049 ,the correlation coefficient r2 =0 .994 4 ,the system shift was passed at the medical decision level .When the specimen concentration within 201-413 .55 mg/L ,the regression line was Y=0 .848X-10 .44 ,the correlation coefficient r2 =0 .917 ,the system shift was not passed at the medical decision level .Conclusion The detection of the Roche ALBU2 in the Cobas 8000 C702 platform can meet the clinical needs ,the comparison among different instruments has difference in different concentration ranges ,therefore the independent reference ranges should be established ac‐cording to the each instrument system .
