Measurement of sirolimus concentrations in human blood using an automated electrochemiluminescence immunoassay (ECLIA): a multicenter evaluation

2018 ◽  
Vol 56 (5) ◽  
pp. 764-775 ◽  
Author(s):  
Veronique Stove ◽  
Pedro Alía Ramos ◽  
Pierre Wallemacq ◽  
Michael Vogeser ◽  
Andre Schuetzenmeister ◽  
...  
Keyword(s):  
Reference Method ◽  
Therapeutic Drug ◽  
Good Precision ◽  
Transplant Recipients ◽  
Intermediate Precision ◽  
Deming Regression ◽  
Limit Of Quantitation ◽  
Liquid Chromatography Tandem Mass ◽  
Chemiluminescent Microparticle Immunoassay ◽  
Electrochemiluminescence Immunoassay

AbstractBackground:Therapeutic drug monitoring (TDM) of sirolimus is essential in transplant recipients. We evaluated the performance of a new electrochemiluminescence immunoassay (ECLIA) for measuring sirolimus concentrations in whole blood at five European laboratories.Methods:Study assessments included repeatability, intermediate precision and functional sensitivity (concentration at coefficient of variation [CV] of 20%) experiments. Method comparisons with liquid chromatography-tandem mass spectrometry (LC-MS/MS; reference method) and two immunoassays (chemiluminescent microparticle immunoassay [CMIA] and antibody-conjugated magnetic immunoassay [ACMIA]) were performed using native samples from patients with kidney transplants.Results:Imprecision testing CVs were ≤6.4% and ≤10.7% across the sirolimus concentration range for both repeatability and intermediate precision, respectively. The ECLIA showed excellent functional sensitivity: the CV did not reach 20%; the CV at the assay’s limit of quantitation (1.5 μg/L) was 7.0%. Agreement between the ECLIA and LC-MS/MS using native kidney samples was close, with weighted Deming regression analysis yielding a slope of 1.05, an intercept of 0.154 μg/L and a Pearson’s correlation coefficient (r) of 0.94, while Bland-Altman analysis showed a combined mean bias of 0.41 μg/L (±2 standard deviation [SD], −1.96 to 2.68). The ECLIA also showed good correlation with the two other immunoassays: the CMIA (slope=0.91, intercept=0.112 μg/L and r=0.89) and the ACMIA (slope=0.99, intercept=0.319 μg/L and r=0.97).Conclusions:The ECLIA showed good precision, functional sensitivity and agreement with other methods of sirolimus measurement used in clinical practice, suggesting that the assay is suitable for TDM in transplant recipients and provides an alternative to LC-MS/MS.

scholarly journals Isotope-Dilution Liquid Chromatography–Tandem Mass Spectrometry Candidate Reference Method for Total Testosterone in Human Serum

2013 ◽  
Vol 59 (2) ◽  
pp. 372-380 ◽  
Author(s):  
Julianne Cook Botelho ◽  
Christopher Shacklady ◽  
Hans C Cooper ◽  
Susan S-C Tai ◽  
Katleen Van Uytfanghe ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Isotope Dilution ◽  
Matrix Effects ◽  
Reference Method ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Deming Regression ◽  
Liquid Chromatography Tandem Mass

BACKGROUND We developed and evaluated a candidate reference measurement procedure (RMP) to standardize testosterone measurements, provide highly accurate and precise value assignments for the CDC Hormone Standardization Program, and ensure accurate and comparable results across testing systems and laboratories. METHODS After 2 liquid/liquid extractions of serum with a combination of ethyl acetate and hexane, we quantified testosterone by isotope-dilution liquid chromatography–tandem mass spectrometry with electrospray ionization in the positive ion mode monitoring 289→97 m/z (testosterone) and 292→112 m/z (3C13 testosterone). We used calibrator bracketing and gravimetric measurements to give higher specificity and accuracy to serum value assignments. The candidate RMP was evaluated for accuracy by use of NIST-certified reference material SRM971 and validated by split-sample comparison to established RMPs. We evaluated intraassay and interassay imprecision, measurement uncertainty, potential interferences, and matrix effects. RESULTS A weighted Deming regression comparison of the candidate RMP to established RMPs showed agreement with no statistical difference (slope 0.99, 95% CI 0.98–1.00, intercept 0.54, 95% CI −1.24 to 2.32) and a bias of ≤0.3% for NIST SRM971. The candidate RMP gave maximum intraassay, interassay, and total percent CVs of 1.5%, 1.4%, and 1.7% across the concentrations of testosterone typically found in healthy men and women. We tested structural analogs of testosterone and 125 serum samples and found no interferences with the measurement. CONCLUSIONS This RMP for testosterone can serve as a higher-order standard for measurement traceability and can be used to provide an accuracy base to which routine methods can be compared in the CDC Hormone Standardization Program.

Evaluation of the MassTrak Immunosuppressant XE Kit for the determination of everolimus and cyclosporin A in human whole blood employing isotopically labeled internal standards

2011 ◽  
Vol 49 (12) ◽  
Author(s):  
Misuk Ji ◽  
Sollip Kim ◽  
Hee-Jung Chung ◽  
Woochang Lee ◽  
Sail Chun ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Cyclosporin A ◽  
Therapeutic Drug ◽  
Tandem Mass ◽  
Transplant Recipients ◽  
Internal Standards ◽  
Human Whole Blood ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

AbstractLiquid chromatography-tandem mass spectrometry (LC-MS/MS) is widely used for therapeutic drug monitoring of immunosuppressants given to transplant recipients. This study evaluated the performance of the newly introduced MassTrak Immunosuppressant XE Kit (Waters Corporation; “the Kit”) in the determination of everolimus and cyclosporin A (CsA) using LC-MS/MS.The linearity, precision, detection limit, carryover and matrix effect of the Kit and comparison of the in-house method and Kit procedure were evaluated according to Clinical and Laboratory Standards Institute guidelines.The Kit afforded good linearity in the measurement of everolimus from 2 to 26 ng/mL (RThe Kit employing isotopically labeled internal standards provides reliable measurements of immunosuppressant levels over a broad range of concentrations.

scholarly journals Quantitative Insulin Analysis Using Liquid Chromatography–Tandem Mass Spectrometry in a High-Throughput Clinical Laboratory

2013 ◽  
Vol 59 (9) ◽  
pp. 1349-1356 ◽  
Author(s):  
Zhaohui Chen ◽  
Michael P Caulfield ◽  
Michael J McPhaul ◽  
Richard E Reitz ◽  
Steven W Taylor ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Human Insulin ◽  
High Throughput ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Deming Regression ◽  
Limit Of Quantitation ◽  
Liquid Chromatography Tandem Mass

BACKGROUND Circulating insulin concentrations reflect the amount of endogenous insulin produced by the pancreas and can be monitored to check for insulin resistance. Insulin is commonly measured using immunochemiluminometric assays (ICMA). Unfortunately, differing crossreactivities of the various ICMA antibodies have led to variability in assay results. In contrast, liquid chromatography–tandem mass spectrometry (LC-MS/MS)-based approaches can provide a highly specific alternative to immunoassays. METHODS Insulin was extracted from patient serum and reduced to liberate the insulin B chain. Subsequent resolution of the peptide was achieved by LC coupled to triple-quadrupole MS. Selected-reaction monitoring of B-chain transitions was used for quantification. Recombinant human insulin was used as a calibrator and was compared against the National Institute for Biological Standards and Control (NIBSC) reference standard. Bovine insulin and a stable isotopic-labeled (13C/15N) human insulin B chain were used and compared as internal standards. RESULTS The LC-MS/MS assay described herein has been validated according to CLIA guidelines with a limit of detection of 1.8 μIU/mL (10.8 pmol/L) and a limit of quantitation of 3 μIU/mL (18.0 pmol/L). A correlation between the LC-MS/MS assay and a US Food and Drug Administration-approved ICMA was completed for patient samples and the resulting Deming regression revealed good agreement. A reference interval for the assay was established. CONCLUSIONS A simple, high-throughput, quantitative LC-MS/MS insulin assay traceable to the NIBSC standard has been successfully developed and validated.

scholarly journals Multicenter performance evaluation of a second generation cortisol assay

2017 ◽  
Vol 55 (6) ◽  
pp. 826-835 ◽  
Author(s):  
Michael Vogeser ◽  
Jürgen Kratzsch ◽  
Yoon Ju Bae ◽  
Mathias Bruegel ◽  
Uta Ceglarek ◽  
...  
Keyword(s):  
Second Generation ◽  
Reference Ranges ◽  
Good Precision ◽  
Healthy Individuals ◽  
Serum Samples ◽  
Intermediate Precision ◽  
Coefficients Of Variation ◽  
Liquid Chromatography Tandem Mass ◽  
Cortisol Levels ◽  
Roche Diagnostics

Abstract Background: Untreated disorders of the adrenocortical system, such as Cushing’s or Addison’s disease, can be fatal, and accurate quantification of a patient’s cortisol levels is vital for diagnosis. The objective of this study was to assess the analytical performance of a new fully-automated Elecsys® Cortisol II assay (second generation) to measure cortisol levels in serum and saliva. Methods: Four European investigational sites assessed the intermediate precision and reproducibility of the Cortisol II assay (Roche Diagnostics) under routine conditions. Method comparisons of the Cortisol II assay vs. liquid chromatography-tandem mass spectrometry (LC-MS/MS), the gold standard for cortisol measurement, were performed. Cortisol reference ranges from three US sites were determined using samples from self-reported healthy individuals. Results: The coefficients of variation (CVs) for repeatability, intermediate precision, and reproducibility for serum samples were ≤2.6%, ≤5.8%, and ≤9.5%, respectively, and for saliva were ≤4.4% and ≤10.9%, and ≤11.4%, respectively. Agreement between the Cortisol II assay and LC-MS/MS in serum samples was close, with a slope of 1.02 and an intercept of 4.473 nmol/L. Reference range samples were collected from healthy individuals (n=300) and serum morning cortisol concentrations (5–95th percentile) were 166.1–507 nmol/L and afternoon concentrations were 73.8–291 nmol/L. Morning, afternoon, and midnight saliva concentrations (95th percentile) were 20.3, 6.94, and 7.56 nmol/L, respectively. Conclusions: The Cortisol II assay had good precision over the entire measuring range and had excellent agreement with LC-MS/MS. This test was found suitable for routine diagnostic application and will be valuable for the diagnosis of adrenocortical diseases.

Immunosuppressive Management of Pediatric Kidney Transplant Recipients

2020 ◽  
Vol 26 (28) ◽  
pp. 3451-3459
Author(s):  
Tomáš Seeman
Keyword(s):  
Immunosuppressive Therapy ◽  
Kidney Transplant ◽  
Induction Therapy ◽  
Graft Loss ◽  
Calcineurin Inhibitors ◽  
Mtor Inhibitors ◽  
Therapeutic Drug ◽  
High Dose ◽  
Transplant Recipients ◽  
Kidney Transplant Recipients

: Kidney transplantation is a preferable treatment of children with end-stage kidney disease. All kidney transplant recipients, including pediatric need immunosuppressive medications to prevent rejection episodes and graft loss. : Induction therapy is used temporarily only immediately following transplantation while maintenance immunosuppressive drugs are started and given long-term. There is currently no consensus regarding the use of induction therapy in children; its use should be decided based on the immunological risk of the child. : The recent progress shows that the recommended strategy is to use as maintenance immunosuppressive therapy a combination of a calcineurin inhibitor (preferably tacrolimus) with an antiproliferative drug (preferably mycophenolate mofetil) with steroids that can be withdrawn early or late in low-risk children. The mTOR-inhibitors (sirolimus, everolimus) are used rarely in pediatrics because of common side effects and no evidence of a benefit over calcineurin inhibitors. The use of calcineurin inhibitors, mycophenolate, and mTOR-inhibitors should be followed by therapeutic drug monitoring. : Immunosuppressive therapy of acute rejection consists of high-dose steroids and/or anti-lymphocyte antibodies (T-cell mediated rejection) or plasma exchange, intravenous immunoglobulines and/or rituximab (antibodymediated rejection). : The future strategies for research are mainly precise characterisation of children needing induction therapy, more specific indications for mTOR-inhibitors and for the far future, the possibility to reach the immuno tolerance.

scholarly journals PERFORMANCE CHARACTERISTICS OF A FRET-BASED IMMUNOASSAY FOR QUANTITATION OF INFLIXIMAB ON A POINT-OF-CARE INSTRUMENT SYSTEM

2021 ◽  
Vol 27 (Supplement_1) ◽  
pp. S57-S57
Author(s):  
Edgar Ong ◽  
Ruo Huang ◽  
Richard Kirkland ◽  
Michael Hale ◽  
Larry Mimms
Keyword(s):  
Whole Blood ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Quantitative Detection ◽  
Therapeutic Drug ◽  
Analytical Sensitivity ◽  
Sample Type ◽  
Hook Effect ◽  
Limit Of Quantitation ◽  
Assay Precision

Abstract Introduction A fast (<5 min), time-resolved fluorescence resonance energy transfer (FRET)-based immunoassay was developed for the quantitative detection of infliximab (IFX) and biosimilars for use in therapeutic drug monitoring using only 20 µL of fingerstick whole blood or serum at the point-of-care. The Procise IFX assay and ProciseDx analyzer are CE-marked. Studies were performed to characterize analytical performance of the Procise IFX assay on the ProciseDx analyzer. Methods Analytical testing was performed by spiking known amounts of IFX into negative serum and whole blood specimens. Analytical sensitivity was determined using limiting concentrations of IFX. Linearity was determined by testing IFX across the assay range. Hook effect was assessed at IFX concentrations beyond levels expected to be found within a patient. Testing of assay precision, cross-reactivity and potential interfering substances, and biosimilars was performed. The Procise IFX assay was also compared head-to-head with another CE-marked assay: LISA-TRACKER infliximab ELISA test (Theradiag, France). The accuracy of the Procise IFX assay is established through calibrators and controls traceable to the WHO 1st International Standard for Infliximab (NIBSC code: 16/170). Results The Procise IFX assay shows a Limit of Blank, Limit of Detection, and Lower Limit of Quantitation (LLoQ) of 0.1, 0.2, and 1.1 µg/mL in serum and 0.6, 1.1, and 1.7 µg/mL in whole blood, respectively. The linear assay range was determined to be 1.7 to 77.2 µg/mL in serum and whole blood. No hook effect was observed at an IFX concentration of 200 µg/mL as the value reported as “>ULoQ”. Assay precision testing across 20 days with multiple runs and reagent lots showed an intra-assay coefficient of variation (CV) of 2.7%, an inter-assay CV of <2%, and a total CV of 3.4%. The presence of potentially interfering/cross-reacting substances showed minimal impact on assay specificity with %bias within ±8% of control. Testing of biosimilars (infliximab-dyyb and infliximab-abda) showed good recovery. A good correlation to the Theradiag infliximab ELISA was obtained for both serum (slope=1.01; r=0.99) and whole blood (slope=1.01; r=0.98) samples (Figure 1). Conclusion Results indicate that the Procise IFX assay is sensitive, specific, and precise yielding results within 5 minutes from both whole blood and serum without the operator needing to specify sample type. Additionally, it shows very good correlation to a comparator assay that takes several hours and sample manipulation to yield results. This makes the Procise IFX assay ideal for obtaining fast and accurate IFX quantitation, thus allowing for immediate drug level dosing decisions to be made by the physician during patient treatment.

scholarly journals Development and Validation of 2-Azaspiro [4,5] Decan-3-One (Impurity A) in Gabapentin Determination Method Using qNMR Spectroscopy

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1656
Author(s):  
Nataliya E. Kuz’mina ◽  
Sergey V. Moiseev ◽  
Mikhail D. Khorolskiy ◽  
Anna I. Lutceva
Keyword(s):  
Test Procedure ◽  
Active Pharmaceutical Ingredient ◽  
Test Methods ◽  
Intermediate Precision ◽  
Coefficients Of Variation ◽  
Validation Parameters ◽  
Limit Of Quantitation ◽  
Student’S T ◽  
Development And Validation ◽  
Student’S T Test

The authors developed a 1H qNMR test procedure for identification and quantification of impurity A present in gabapentin active pharmaceutical ingredient (API) and gabapentin products. The validation studies helped to determine the limit of quantitation and assess linearity, accuracy, repeatability, intermediate precision, specificity, and robustness of the procedure. Spike-and-recovery assays were used to calculate standard deviations, coefficients of variation, confidence intervals, bias, Fisher’s F test, and Student’s t-test for assay results. The obtained statistical values satisfy the acceptance criteria for the validation parameters. The authors compared the results of impurity A quantification in gabapentin APIs and capsules by using the 1H qNMR and HPLC test methods.

scholarly journals Simultaneous quantitation of five triazole anti-fungal agents by paper spray-mass spectrometry

2020 ◽  
Vol 58 (5) ◽  
pp. 836-846 ◽  
Author(s):  
Christine L. Skaggs ◽  
Greta J. Ren ◽  
El Taher M. Elgierari ◽  
Lillian R. Sturmer ◽  
Run Z. Shi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Therapeutic Drug ◽  
Reference Laboratory ◽  
Triple Quadrupole Mass Spectrometer ◽  
Limit Of Quantification ◽  
Paper Spray ◽  
Calibration Curves ◽  
Drug Concentrations ◽  
Limit Of Quantitation ◽  
Anti Fungal

AbstractBackgroundInvasive fungal disease is a life-threatening condition that can be challenging to treat due to pathogen resistance, drug toxicity, and therapeutic failure secondary to suboptimal drug concentrations. Frequent therapeutic drug monitoring (TDM) is required for some anti-fungal agents to overcome these issues. Unfortunately, TDM at the institutional level is difficult, and samples are often sent to a commercial reference laboratory for analysis. To address this gap, the first paper spray-mass spectrometry assay for the simultaneous quantitation of five triazoles was developed.MethodsCalibration curves for fluconazole, posaconazole, itraconazole, hydroxyitraconazole, and voriconazole were created utilizing plasma-based calibrants and four stable isotopic internal standards. No sample preparation was needed. Plasma samples were spotted on a paper substrate in pre-manufactured plastic cartridges, and the dried plasma spots were analyzed directly utilizing paper spray-mass spectrometry (paper spray MS/MS). All experiments were performed on a Thermo Scientific TSQ Vantage triple quadrupole mass spectrometer.ResultsThe calibration curves for the five anti-fungal agents showed good linearity (R2 = 0.98–1.00). The measured assay ranges (lower limit of quantification [LLOQ]–upper limit of quantitation [ULOQ]) for fluconazole, posaconazole, itraconazole, hydroxyitraconazole, and voriconazole were 0.5–50 μg/mL, 0.1–10 μg/mL, 0.1–10 μg/mL, 0.1–10 μg/mL, and 0.1–10 μg/mL, respectively. The inter- and intra-day accuracy and precision were less than 25% over the respective ranges.ConclusionsWe developed the first rapid paper spray-MS/MS assay for simultaneous quantitation of five triazole anti-fungal agents in plasma. The method may be a powerful tool for near-point-of-care TDM aimed at improving patient care by reducing the turnaround time and for use in clinical research.

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