Internal Proficiency Testing Research Articles

A threshold LC–MS/MS method for 92 analytes in oral fluid collected with the Quantisal® device

A study of impaired driving rates in the province of Québec is currently planned following the legalization of recreational cannabis in Canada. Oral fluid (OF) samples are to be collected with a Quantisal® device and sent to the laboratory for analysis. In order to prepare for this project, a qualitative decision point analysis method monitoring for the presence of 97 drugs and metabolites in OF was developed and validated.This high throughput method uses incubation with a precipitation solvent (acetone:acetonitrile 30:70 v:v) to boost drug recovery from the collecting device and improve stability of benzodiazepines (e.g., α-hydroxyalprazolam, clonazepam, 7-aminoclonazepam, flunitrazepam, 7-aminoflunitrazepam, N-desmethylflunitrazepam, nitrazepam). The Quantisal® device has polyglycol in its stabilizing buffer, but timed use of the mass spectrometer waste valve proved sufficient to avoid the glycol interferences for nearly all analytes. Interferences from OF matrices and 140 potentially interfering compounds, carryover, ion ratios, stability, recovery, reproducibility, robustness, false positive rate, false negative rate, selectivity, sensitivity and reliability rates were tested in the validation process. Five of the targeted analytes (olanzapine, oxazepam, 7-aminoclonazepam, flunitrazepam and nitrazepam) did not meet the set validation criteria but will be monitored for identification purposes (no comparison to a cut-off level).Blind internal proficiency testing was performed, where six OF samples were tested and analytes were classified as “negative”, “likely positive” or “positive” with success. The final validated OF qualitative decision point method covers 92 analytes, and the presence of 5 additional analytes is screened in this high throughput analysis.

Screening of Weight-Loss Herbal Products for Synthetic Anti-Obesity Adulterants: A Target-Oriented Analysis by Liquid Chromatography–Tandem Mass Spectrometry

Background The medical and social impact of being overweight, as well as the difficulty in making long-term changes in diet, physical activity, and pitfalls associated with allopathic management, lure obese individuals to over-the-counter weight-loss herbal products (WHPs). However, the safety of herbals is questionable, as reports from all over the world suggest adulteration with synthetic weight loss agents. Objective: The present study was carried out to develop a rapid and sensitive method to screen potential weight loss adulterants in WHPs. Methodology: We procured 33 licensed brands of WHPs that are available in Puducherry (India) and through web stores. Drug-free spiked herbal matrices were used for internal proficiency testing. Spiked herbal matrices and samples were extracted and centrifuged. The supernatant was collected and subjected to liquid chromatography–tandem mass spectrometry analyses. Isocratic elution was carried out by the mobile phase of methanol: 0.1% v/v formic acid (70%:30% v/v) through a C18 column. Analytes were monitored in electrospray ionization positive and negative modes, and an multiple reaction monitoring (MRM) scan was used. Results: Run time was 12 min. Intra- and inter-day precision was < 15% and recoveries were in the range of 99% to 115%. Limit of quantification (LOQ) of the analytes were in the range of 0.1 to 0.3 ng/ml. Conclusion: We developed a sensitive and rapid validated method for the detection of potential adulterants in WHPs. None of the WHPs analyzed were found to contain adulterants. The proposed method will be useful for routine monitoring. WHPs analyzed in this study were not adulterated indicating that WHPs from licensed sources are reliable.

Determining and Validating the Minimum Number of Patient Specimens for Internal Proficiency Testing of Glucose Meters

s: Critical and Point-of-Care Testing: Managing Technology for the Benefit of All Populations: 22nd International Symposium: September 17-20, 2008: Catalonia Barcelona Plaza Hotel|Barcelona, Spain

Responsabilidases de fabricantes y ususarios finales en la validación de kits de diagnóstico y viligencia de las enfermedades del ganado

The Joint Food and Agriculture Organization/International Atomic Energy Agency (IAEA) Division of Nuclear Techniques in Food and Agriculture, based at the IAEA in Vienna, Austria, has extensive experience in helping to develop and validate assays and has provided strong support in developing World Organisation for Animal Health (OIE) norms. This paper will focus on enzyme-linked immunosorbent assay and polymerase chain reaction as the major technologies exploited in diagnosis and surveillance. Problems involving the terminology and factors in kit production, supply and validation are examined, in particular emphasising the importance of robustness and ruggedness of tests. The authors discuss the responsibilities of the various stakeholders (producers, distributors, users, and national/international organisations) in achieving quality controlled data to solve diagnostic and surveillance problems. The roles of internal quality control (internal proficiency testing) and external quality assurance (external proficiency testing) as well as aids to solving problems with kits are examined.

Application of LC–ESI–MS–MS for detection of synthetic adulterants in herbal remedies

Adulteration of allegedly “natural herbal medicines” with undeclared synthetic drugs is a common and dangerous phenomenon of alternative medicine. The purpose of the study was to develop a procedure for detection of most common synthetic adulterants in herbal remedies, using high-pressure liquid chromatography-electrospray tandem mass spectrometry (LC–ESI–MS–MS). Eighty drugs belonging to various pharmacological classes were included in the study. For most drugs two transitions were monitored, using protonated or deprotonated molecules as precursor ions. The drugs were isolated from herbal remedies using simple methanol extraction. Chromatographic separation was done in gradient of acetonitrile—10 mM ammonium formate buffer (pH 3.0). Drugs tested were grouped in suites, comprising analgesic drugs, antibiotics, antidiabetic drugs, antiepileptic drugs, aphrodisiacs, hormones and anabolic drugs, psychotropic drugs, and weight reducing compounds. These suites were used according to the declared benefits of examined preparations. Limits of detection ranged from 5 pg to 1 ng per injected sample. Drug-free herbal remedy spiked with eight various pharmaceuticals occurring in adulterated herbal preparations was used for internal proficiency testing. The recoveries of spiked drugs ranged from 63 to 100%. The procedure was applied in everyday casework. Several undeclared drugs were identified in “herbal” remedies, like e.g. sildenafil, tadalafil, testosterone, or glibenclamide. Pharmacological properties of detected drugs always corresponded with the claims of the “natural” remedies. The method presents a valuable extension of standard GC–MS screening used for this purpose.

The quality assurance of proficiency testing programs for animal disease diagnostic laboratories.

Laboratory data credibility has 3 major components: 1) valid methods, 2) proficiency testing (PT) to verify that the analyst can conduct the method and to compare results of other laboratories using the same method, and 3) third-party accreditation to verify that the laboratory is competent to conduct testing and that the method validation has been done within the environment and requirements of an effective quality-management system. Participation in external PT programs by a laboratory is strongly recommended in International Organization for Standardization/International Electrotechnical Commission International Standard 17025. Most laboratory accreditation bodies using this standard require that laboratories participate in such programs to be accredited. Internal PT is also recommended for each analyst. Benchmarking, or comparison between laboratories using PT or reference materials, is also recommended as part of the validation and evaluation of test methods. These requirements emphasize the need for proficiency test providers to demonstrate their competence. Requirements for competence are documented in national and international standards and guidelines, and accreditation is available for providers. This article discusses the activities and the components that are necessary and recommended for PT projects and programs for animal disease diagnostic testing. These are based on the requirements of the national and international standards, which address this subject, and on the experience of the author. The accreditation of external PT programs is also discussed. Organizations that accredit PT providers or that provide PT programs are listed. Existing references, guidelines, and standards that are relevant to PT in veterinary diagnostic laboratories are discussed.