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At least 19 recordsLinked to original sources
PubMed1991

Use of quality control standards in clinical flow cytometry.

Flow cytometry is important in the clinical laboratory, especially in hematology and cancer diagnosis. With newer applications being continuously developed clinicians who will use the results and laboratory staff who produce them should be aware of the instrumental quality control procedures required. This will allow evaluation of the reliability as well as the comparison of results between different laboratories. While information about sample preparation as well as staining procedures is easily available, information about instrumental quality control procedures is less so. Various standards and controls are available commercially and their correct choice and usage requires an understanding of the methodology of instrumental quality control. Methods to evaluate the precision, sensitivity and accuracy of measurements are discussed. Most laboratories report immunophenotyping data as the percentage of antibody positive cells and make no attempt to quantitate the amount of antibody binding per cell. Methods for quantitating the number of bound antibody molecules per cell along with a simple technique to compare results between laboratories are discussed. These techniques should encourage laboratory staff and clinicians to standardise methodology and to exchange patient data between laboratories.

Flow Cytometry↗
PubMed1978

Serum cholesterol analysis in the C.B. Heart Project. Intra-and inter-laboratory continuous quality control.

Standardization and quality control of measurements are of crucial importance in large medical surveys. In the C.B. Heart Project serum cholesterol analyses in the central laboratory were extensively controlled with regard to precision as well as accuracy. All measurements are carried out in side-by-side duplicate, the maximum difference allowed being 0.3 mmol/l. Bench control, aiming at maintaining linearity and precision with control limits, requires insertion of standard solutions and several serum controls into every run. Control values must fall within 2 S.D. limits from the established mean values, e.g. 4.1 +/1 0.25 mmol/l and 8.2 +/- 0.25 mmol/l. A very reliable check on the precision was obtained by blind introduction of duplicate patient specimens. Repeatability (within-run precision) as calculated each month has S.D. values of approx. 0.10--0.20 mmol/l, whereas reproducibility (long-term precision) S.D. values are 0.15--0.25 mmol/l. Accuracy is checked in the Cooperative Standardization Programme of the WHO Regional Lipid Reference Centre in Prague. This makes the C.B. Heart Progject results comparable with other standardized studies. Our bias approximates +3% and usually remains within WHO "narrow limits".

Cholesterol↗
PubMed1990

Method validation in the bioanalytical laboratory.

Bioanalytical methods, based on a variety of physico-chemical and biological techniques such as chromatography, immunoassay and mass spectrometry, must be validated prior to and during use to engender confidence in the results generated. The fundamental criteria for assessing the reliability and overall performance of a bioanalytical method are: the evaluation of drug and analyte stability, selectivity, limits of quantification and detection, accuracy, precision, linearity and recovery. The extent to which a method is validated is dependent on its prospective use, the number of samples to be assayed and the use to which the data are put. Specific analytical techniques may require additional validation such as antibody-binding characteristics, peak purity determination, evaluation of matrix effects or structural confirmation of the analyte. Ideally each assay should be cross-validated with a method utilizing a highly specific detector such as a mass spectrometer. Once in use, the performance of the method should be monitored using quality control standards. If a method is set up in another laboratory, the performance of that assay should be monitored with quality control standards sent from the originating laboratory.

Chemistry, Pharmaceutical↗
PubMed1977

Effect of antilyphocyte-globulin potency on survival of cadaver renal transplants. Prospective randomised double-blind trial.

71 recipients of cadaver primary and secondary renal transplants were investigated in a prospective randomised double-blind study. Patients were given one of two rabbit antilymphocyte globulin (A.L.G.) preparations made by similar techniques but differing in potency as measured by skin-graft prolongation in rhesus monkeys. Patient selection and management were otherwise similar. A statistically significant difference (P less than 0-05) in graft survival (78% vs. 42%) developed between the two groups at a mean follow-up of 18-4 months and patient entry into the study was terminated. After a 3-5 year interval from the start of the trial the double-blind code was broken. It was found that the high-potency-A.L.G. group had better graft survival and fewer rejection episodes (P less than 0-05) than the moderate-potency group. The results suggest that preclinical testing of A.L.G. by the primate skin graft test can be a valid indicator of the potential efficacy of an A.L.G. preparation in renal-transplant recipients. It is suggested that quality-control standards may improve the clinical results of A.L.G. therapy.

Adolescent↗
PubMedDate not supplied

Determination of MDL 201,012 at femtomole/millilitre levels in human plasma by liquid chromatography with electrochemical detection.

A sensitive and selective liquid chromatographic method to quantitate MDL 201,012 in human plasma was developed and validated. MDL 201,012 (I), diethyl-MDL 201,012 (internal standard, II) and desmethyldiol-MDL 201,012 (masking agent, III) were isolated from basified plasma (2 mL) by solid phase extraction using Bond-Elut C-18 cartridges. Endogenous components were selectively removed prior to eluting the analytes from the sorbent. Components were separated using on-line LC column switching with a cyanopropyl precolumn and a phenyl analytical column. The analytical column effluent was monitored electrochemically at a glassy carbon electrode at a potential of +1025 mV vs. Ag/AgCl. Peak-height ratios were proportional to the amount of MDL 201,012 added to plasma over the range 125-7500 pg/mL MDL 201,012. Absolute recovery of MDL 201,012 from human plasma was > 94% across the calibration range. The minimum quantitation limit was 125 pg/mL. Assay precision (%RSD) ranged from 5.2 to 13% based on the analysis of quality control standards containing 125, 250, 500, 1000, 2500, 5000 and 7500 pg/mL MDL 201,012. Corresponding assay accuracy (% relative error) was +/- 8.5%. The method has been successfully used to quantitate MDL 201,012 in samples from acute dose tolerance studies in human volunteers.

Alkynes↗
PubMed2025

Mendelian randomization underscores the importance of clinical nursing in mitigating anxiety and panic attack risks among low-educated populations.

Considering the complex and underexplored interplay between educational attainment (EA) and the prevalence of anxiety and panic attacks, which carries significant societal implications, we have designed a two-sample Mendelian randomization (MR) study. The primary objective of this research is to elucidate the causal relationship between education level and the risk of anxiety and panic attacks, thereby providing novel insights for clinical and nursing strategies. Our study adheres to the STROBE-MR guidelines and employs a classical two-sample MR analysis to investigate the causal relationship between EA (exposure) and the occurrence of anxiety/panic attacks (outcome). The data for 8 education-related phenotypes, along with anxiety and panic attack outcomes, were sourced from European population-based Genome-wide association studies databases. To ensure robustness, we applied 5 distinct MR analytical methods, supplemented by comprehensive sensitivity analyses, heterogeneity assessments, and evaluations of reverse causality bias to uphold rigorous quality control standards. Our findings, robust across various MR methods and consistent after inverse variance-weighted and false discovery rate (FDR) corrections, indicate a significant association between lower EA and an increased risk of anxiety or panic attacks. Specifically, individuals with no formal qualifications exhibited a higher risk (P-value&#x2005;=&#x2005;.005, OR&#x2005;=&#x2005;1.017, 95% CI&#x2005;=&#x2005;1.005-1.029, FDR&#x2005;=&#x2005;0.011). In contrast, higher levels of education were associated with a reduced risk: College or University degree (P-value&#x2005;<&#x2005;.01, OR&#x2005;=&#x2005;0.989, 95% CI&#x2005;=&#x2005;0.984-0.995, FDR&#x2005;=&#x2005;0.0007), EA (P-value&#x2005;<&#x2005;.01, OR&#x2005;=&#x2005;0.999, 95% CI&#x2005;=&#x2005;0.998-0.9995, FDR&#x2005;=&#x2005;0.0009), and A levels/AS levels or equivalent (P-value&#x2005;=&#x2005;.011, OR&#x2005;=&#x2005;0.988, 95% CI&#x2005;=&#x2005;0.978-0.997, FDR&#x2005;=&#x2005;0.019). These conclusions were consistently supported by at least 4 MR methods and successfully passed all quality control checks. Our study demonstrates a negative correlation between years of education and the risk of anxiety and panic attacks, suggesting that clinical nursing and patient education efforts should prioritize tailored psychological support and patient communication for individuals with lower EA. This population warrants enhanced attention and more compassionate care to mitigate their elevated risk of anxiety-related disorders.

Humans↗
PubMed1979

The use and interpretation of RAST to stinging insect venoms.

Quality controlled, standardized RAST systems for five stinging insect venoms are described. These systems were evaluated using 375 sera from insect reactive patients from six diverse geographic regions. Ninety-four percent of patients with recent histories of systemic allergic reactions to stings were positive to at least one venom while 4 percent of normal local reactors were positive. The cross reactions between honey bee and vespid venoms were studied by RAST inhibition. A quantitative method for interpretation of venom RAST is presented to account for cross-reactivities and the approach to diagnosis is discussed.

Animals↗
PubMed1990

Standardization and harmonization of the blood count: the role of International Committee for Standardization in Haematology (ICSH).

Scientific principles of standardization were first applied in haematology in 1963 when the International Committee for Standardization in Haematology was established with a primary objective to improve the measurement of haemoglobin. Subsequently, ICSH has established Expert Panels on a wide range of haematological topics, including especially a Panel on Cytometry. The purpose of haematological standardization is to obtain precision, accuracy, specificity and harmonization of results between different laboratories in all countries and also between different instruments or methods in the same laboratory. To achieve these objectives ICSH sponsors collaborative studies by scientists from academic centres and from industry and uses a consensus procedure for establishing standards on the basis of the scientific data, followed by an educational programme to ensure that the standards are adopted worldwide. ICSH defines material standards and standardized methods. Material standards are classified as primary international standards, certified reference materials, secondary standards and calibrators. These must be distinguished from control preparations which are intended exclusively for quality control. Standardization of methods must also be considered at four levels: definitive, reference, selected and routine. Each has a place in practice but their roles must be clearly defined. ICSH has an established protocol for evaluation of automated blood cell counters. This defines the levels of precision and accuracy of instrument performance. It is also necessary to assess "clinical utility". The main requirement of the practising haematologist is clinical reliability and harmonization of results for comparability. One of the major functions of ICSH is to provide an interface for collaboration between the manufacturers who develop the instruments and the users in order to achieve this goal.

Anticoagulants↗
PubMed1991

False resistance to imipenem with a microdilution susceptibility testing system.

Routine monitoring of antibiotic resistance at Children's Hospital, Boston, detected a dramatic increase in the prevalence of imipenem-resistant strains of Pseudomonas aeruginosa. Further studies documented that false resistance to imipenem was due, in part, to the loss of imipenem potency in customized MIC microdilution trays supplied by Sensititre Ltd. (West Sussex, United Kingdom). Recognition of the problem was delayed by use of the quality control standard recommended by the manufacturer, which were higher and broader than those suggested by the National Committee for Clinical Laboratory Standards.

Cystic Fibrosis↗
PubMed1992

Anatomy of a defective barrier: sequential glove leak detection in a surgical and dental environment.

OBJECTIVES: a) To determine the frequency of perforations in latex surgical gloves before, during, and after surgical and dental procedures; b) to evaluate the topographical distribution of perforations in latex surgical gloves after surgical and dental procedures; and c) to validate methods of testing for latex surgical glove patency. DESIGN: Multitrial tests under in vitro conditions and a prospective sequential patient study using consecutive testing. SETTING: An outpatient dental clinic at a university dental school, the operating suite in a medical school affiliated with the Veteran's Hospital, and a biomechanics laboratory. PERSONNEL: Surgeons, scrub nurses, and dental technicians participating in 50 surgical and 50 dental procedures. METHODS: We collected 679 latex surgical gloves after surgical procedures and tested them for patency by using a water pressure test. We also employed an electronic glove leak detector before donning, after sequential time intervals, and upon termination of 47 surgical (sequential surgical), 50 dental (sequential dental), and in three orthopedic cases where double gloving was used. The electronic glove leak detector was validated by using electronic point-by-point surface probing, fluorescein dye diffusion, as well as detecting glove punctures made with a 27-gauge needle. RESULTS: The random study indicated a leak rate of 33.0% (224 out of 679) in latex surgical gloves; the sequential surgical study demonstrated patency in 203 out of 347 gloves (58.5%); the sequential dental study showed 34 leaks in the 106 gloves used (32.1%); and with double gloving, the leak rate decreased to 25.0% (13 of 52 gloves tested). While the allowable FDA defect rate for unused latex surgical gloves is 1.5%, we noted defect rates in unused gloves of 5.5% in the sequential surgical, 1.9% in the sequential dental, and 4.0% in our electronic glove leak detector validating study. In the sequential surgical study, 52% of the leaks had occurred by 75 mins, and in the sequential dental study, 75% of the leaks developed by 30 mins. In terms of the anatomical localization, the thumb and forefinger accounted for more than 60% of the defects. There were no differences in the frequency of glove leaks between the left and right hand. Leak rates were highest for the surgeon (52%), followed by the first assistant (29%) and the scrub nurse (25%). No false negatives were noted using the electronic glove leak detector; one false positive was seen out of 225 gloves tested (0.44%), as noted in our validation studies. CONCLUSIONS: Significantly high glove leak rates were noted after surgical and dental procedures, indicating that the present day latex surgical gloves can become an incompetent barrier once they are used. Unused latex surgical gloves demonstrated a higher rate of defects than allowed by the Food and Drug Administration standards, indicating substantial noncompliance of quality control standards by manufacturers as well as inadequate governmental oversight. Double gloving, or the use of thicker latex surgical gloves, would probably reduce the frequency of glove leaks. Latex surgical gloves should be tested for patency before use and during surgical and dental procedures.

Dentistry↗
PubMed1977

What is quality care? A clinician's view.

The prospect of national health insurance means the establishment of government criteria for reimbursable psychiatric treatment. These cost-control standards are certain to be justified on the basis of quality maintenance as well. Such preestablished criteria would not only fail to insure quality, they would likely undermine it. Steps toward an urgently needed definition of "quality treatment" are considered.

Cost-Benefit Analysis↗
PubMed1992

[Quality control in hematology].

Qualified quality control is a necessary part of modern haematology: we cannot deem laboratory results reliable until effective quality checking is included. Quality assessment includes external (national, regional) and internal (intra-laboratory) control. We suggest to found a Czech national external quality control agency for haematology based on principles which were declared by the World Health Organization. Internal control includes correct identification of samples, analytical control (standardization of test, evaluation of accuracy and precision) and biological quality control (history of patient's characteristics, relation to other laboratory results in clinical context). The deviation index, which is expressed either as a number or verbally 'excellent', 'good', 'satisfactory', or 'unsatisfactory', can supply rapid information on the quality of results in the haematological laboratory.

Hematology↗
PubMed1991

[Status quo and prospects of oral liquid prepared from Chinese drugs].

This paper reviews the rise of oral liquids and their preparations, control standards, pharmacological research and clinical pharmacy, etc. On the basis of investigation, an overall discussion is given in respect to product variety and sale, pharmaceutical research and development, and social benefit from new products, so as to highlight the merits of Chinese medicinal materials.

Administration, Oral↗
PubMed2026

Seed-derived mucilage polysaccharides as biomaterials for in vivo tissue regeneration: A systematic review.

Chronic wounds, bone defects, and cartilage injuries represent persistent clinical challenges requiring biomaterial platforms that actively regulate inflammation, oxidative stress, angiogenesis, and extracellular matrix remodeling. Conventional synthetic dressings often provide limited biological activity in these contexts. Seed-derived mucilages - polysaccharide-rich hydrocolloids obtained from chia (Salvia hispanica), flaxseed (Linum usitatissimum), fenugreek (Trigonella foenum-graecum), psyllium (Plantago ovata), guar (Cyamopsis tetragonoloba), quince (Cydonia oblonga) etc. - have emerged as biocompatible, biodegradable, and chemically versatile platforms for tissue engineering. This systematic review, conducted according to PRISMA 2020 guidelines, synthesized in vivo evidence on seed-derived mucilage-based biomaterials across wound healing, bone repair, cartilage regeneration, and related applications. PubMed, Scopus, and Web of Science Core Collection were searched for original in vivo experimental studies published in English between 2020 and 2026. Eligible studies reported at least one measurable regenerative outcome. Data were extracted independently by two reviewers, and methodological quality was assessed using the SYRCLE Risk of Bias tool. Forty-three studies were included. Hydrogels were the dominant biomaterial format, followed by films, scaffolds, sponges, nanoparticle systems, and bilayer or Janus composites. Included systems generally improved wound closure, re-epithelialization, collagen deposition, angiogenesis, antioxidant defense, and inflammatory regulation. However, most studies used small animals with short follow-up periods, and many incorporated nanoparticles or bioactive agents, limiting attribution of efficacy to the mucilage matrix alone. Risk of bias was predominantly unclear due to insufficient reporting of randomization and blinding. Blank mucilage controls, standardized characterization, long-term biosafety data, and clinically relevant models are essential prerequisites for translational progress.

Humans↗
PubMed1990

Cholesterol screening: comparative evaluation of on-site and laboratory-based measurements.

We measured cholesterol in capillary blood samples from 9683 volunteers over a four-day on-site community screening program, using the "Reflotron" desk-top analyzer (Boehringer-Mannheim Diagnostics, Indianapolis, IN). We also measured cholesterol in venous blood samples from 3% of those screened (a) with the Reflotron at the screening sites, (b) in a qualified hospital clinical laboratory, and (c) in a Centers for Disease Control standardized lipoprotein research laboratory. The sensitivity (and specificity) of the Reflotron measurements, with use of the lipoprotein laboratory measurements as the point of reference, was 0.95 (0.73) in capillary blood samples and 0.88 (0.93) in venous blood samples, compared with 0.99 (0.87) in the hospital clinical laboratory. The Reflotron measurements correlated less well with the lipoprotein laboratory values in both venous blood (r = 0.91) and capillary blood (r = 0.89) samples than did the clinical laboratory values (r greater than 0.99). Furthermore, the capillary blood measurements averaged 7% higher than venous measurements when both kinds of samples were analyzed in the Reflotron.

Adult↗
PubMed1990

The advent of clinical standards for professional liability.

The development of clinically based written standards to reduce the frequency and severity of medical malpractice loss appears to be gaining in popularity among provider specialty groups and professional liability underwriters. To date, such standards have addressed problems in specialties such as obstetrics and anesthesia where dollar losses associated with malpractice claims have been high. Guidelines can be developed and used by providers on a purely voluntary basis or mandated on an involuntary basis by third parties such as malpractice insurance companies or legislators. Because the advent of risk-control standards is a relatively new phenomenon, formal scientific studies on the long-term benefits of such guidelines have not yet been published. However, it appears that sharp reductions of malpractice losses in specialties such as anesthesia have coincided with the implementation of formal written standards specifically designed for liability control. This has led some liability insurance carriers to decrease premiums associated with specialists following such standards. Many providers are understandably concerned about the potential use of written standards by plaintiff attorneys in medical malpractice suits. Although it is possible that such policies and guidelines could be admitted into evidence to show that a provider breached the legal duty or standard of care owed to a patient, it is uncertain whether these risk-control standards could ultimately pass the evidentiary rules of relevancy or materiality in a given lawsuit. It is clear, however, that the consensus-based process of creating clinical standards and guidelines specifically for controlling professional liability losses is itself a powerful and emerging standard for health care risk management programs.

Clinical Competence↗
PubMed1978

[Problems in production, control and utilization of veterinary vaccines in the developing countries].

For a whole series of reasons, most of which are political, the developing countries are following a policy of national self-sufficiency in veterinary vaccines. They are faced with problems at various levels: (1) at the level of logistic distribution, the developing countries suffer from a shortage of trained personnel, frequently lacking in enthusiasm, an often chronic shortage of funds; poorly equipped premises; poor maintenance of sophisticated but indispensable equipment (e.g. freeze-driers); a lack of facilities for cold storage and of distribution channels; field personnel with limited experience; (2) at the level of production, they must contend with difficulties in obtaining supplies of flasks and glassware; irregular supplies of water and electricity; difficulties in obtaining susceptible animals for quality control. The developing countries have found basically pragmatic solutions to these problems, such as the strict separation of the sites, materials and personnel involved in routine diagnosis and those involved in production; temporary foreign technical assistance, with or without financial aid; the use of simple, unsophisticated techniques, which are known to be reliable, even if somewhat outdated; manufacturing in bulk in multiple-dose bottles; research into the thermostabilisation of vaccine strains and the development of thermoprotective diluents for freeze-drying and reconstitution; the extensive use of combined vaccines; the establishment of production and control standards under the auspices of the WHO/FAO/OIE. In spite of these obstacles, the cost price is particularly low (from 0.20 to 0.35 francs per dose), which compares favourably with that of foreign private industry.

Africa↗