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PubMed2000

[Quality control for HLA typing].

In November 1999 we started the quality control exercise for Polish institutions involved in HLA typing. Five out of eleven invited institutions responded favourably and took part in the first run of the workshop. In the second trial, presently reported, number of labs increased to eight. Each centre received 4 blood samples for serological typing of HLA class I and 5 samples for DNA HLA class II typing. As in the previous workshop, HLA class II typing should be performed at least for DRB1 alleles at the low resolution level. The paper presents the results of the second run of standardisation.

HLA-DQ Antigens↗
PubMedDate not supplied

Comparison of three analytical methods for quality control of clozapine tablets.

Three different analytical methods for the quality control of clozapine in commercial formulations were developed and compared: a liquid chromatographic (LC) method with UV detection, a capillary zone electrophoretic (CZE) method, and a linear scan voltammetric (LSV) method. The isocratic LC procedure used a C18 reversed-phase column; the CZE method used an uncoated fused-silica capillary and phosphate buffer containing polyvinylpyrrolidone as the background electrolyte; the LSV method analyzed clozapine solutions with acidic phosphate buffer as the supporting electrolyte. The 3 methods gave similar and satisfactory results, in terms of precision and accuracy. Repeatability and intermediate precision were good (RSD% < 2.2) and accuracy, resulting from recovery studies, was between 98 and 102%. The rapidity of analysis was high for all 3 methods, especially for the LSV.

Antipsychotic Agents↗
PubMed2002

The unfolded protein response in a dolichyl phosphate mannose-deficient Chinese hamster ovary cell line points out the key role of a demannosylation step in the quality-control mechanism of N-glycoproteins.

The CHO (Chinese hamster ovary) glycosylation mutant cell line, B3F7, transfers the truncated glycan Glc(3)Man(5)GlcNAc(2) on to nascent proteins. After deglucosylation, the resulting Man(5)GlcNAc(2) glycan is subjected to two reciprocal enzymic processes: the action of an endoplasmic-reticulum (ER) kifunensine-sensitive alpha1,2-mannosidase activity to yield a Man(4)GlcNAc(2) glycan, and the reglucosylation involved in the quality-control system which ensures that only correctly folded glycoproteins leave the ER. We show that the recombinant secreted alkaline phosphatase (SeAP) produced in stably transfected B3F7 cells, is co-immunoprecipitated with the GRP78 (glucose-regulated protein 78), a protein marker of the unfolded protein response (UPR). The level of GRP78 transcription has been evaluated by reverse transcription-PCR (RT-PCR) and we demonstrate that B3F7 cells present a constitutively higher level of UPR in the absence of inductors, compared with Pro(-5) cells. Interestingly, a decrease was observed in the UPR and an increase in SeAP secretion in the kifunensine-treated B3F7 cells. Altogether, these data highlight the relationships between the glycan structure, the quality control system and the UPR. Moreover, they support the idea that a specific demannosylation step is a key event of the glycoprotein quality control in B3F7 cells.

Actins↗
PubMedDate not supplied

Quality control measures for cervical cytology laboratories.

The results of three quality control measures for evaluating a cytopathology laboratory's performance in the diagnosis of cervical abnormalities are presented. The sensitivities of cervical cytology were estimated to be 95.5% or 93.1% (using two different methods of analysis) for the detection of histologically diagnosed invasive squamous cell carcinoma of the cervix and 60% for the detection of adenocarcinoma and adenosquamous carcinoma of the cervix in 1983. The positive predictive values for a histologic diagnosis of neoplasia after cytologic reports of CIN III and invasive carcinoma were 92.5% and 99%, respectively. Repeatability of a negative cytologic result exceeded 98%. These results indicate that accurate cervical cytologic reporting can be achieved. Regular monitoring of the type described, which is both practical and reasonably comprehensive, is recommended for all laboratories.

Adenocarcinoma↗
PubMed1995

Tests for susceptibility of Streptococcus pneumoniae to cefdinir: proposed interpretive criteria and quality control parameters for both microdilution and disc diffusion methods.

Proposed quality control (QC) parameters for susceptibility testing of Streptococcus pneumoniae to cefdinir were developed following the procedure recommended by the National Committee for Clinical Laboratory Standards. The proposed QC MIC range for microdilution susceptibility testing of S. pneumoniae ATCC 49619 is 0.06-0.25 mg/L. The proposed QC limits for inhibitory zone diameters of S. pneumoniae ATCC 49619 around 5 micrograms cefdinir disks is 26-31 mm. We recommend the following for tentative interpretive criteria for determining the susceptibility of S. pneumoniae to cefdinir: susceptible, MIC < or = 0.5 mg/L or inhibition zone diameter > or = 23 mm; intermediate, MIC 1.0 mg/L or inhibition zone, 20-22 mm; resistant, MIC > or = 2.0 mg/L or inhibition zone diameter, < or = 19 mm for broth microdilution and disc diffusion tests, respectively.

Cefdinir↗
PubMed1981

A simple strategy convenient for processing of RIA data and quality control in the laboratory on a desk-top-calculator.

The experience with a computer strategy of mathematically simple models for the description of standard curves and continuous quality control calculations with outlier diagnostics for the processing of RIA data in laboratory is discussed. To get over the difficulties associated with the approximation of the nonlinear shape of standard curves, the combination of weighted iterative linear logit-log regression and point-to point logit-log interpolation is proposed. Monitoring of assay performance is based on three large pool sera determined in triplicates. The control data are checked by statistical tests for the rejection of single outlying observations, followed by calculation of objective criteria on within- and between-assay precision by means of analysis of variance for a one-way classification on the basis of which actual triplicates and whole assays can be assessed. Combined with quality control chart technique and the construction of a rough three-point precision profile the empirical knowledge of an experienced assayist should be included in the RIA interpretation as can be easily organized by way of a dialogue-program on a desk-top-calculator.

Computers↗
PubMed1988

Quality control system promotes accountability.

Catholic Health Corporation's (CHC) comprehensive quality control system is an integrated network of review and feedback mechanisms. The mechanisms apply to many facilities and may help them to enhance services and to follow more closely in the Church's tradition of teaching through example. The operational model adapted for use here suggests a system of checks and balances of the following planning, management, and governance functions: Selecting a CEO. Updating strategic plan. Updating mission and philosophy statements. Setting CEO performance objectives. Developing value-based administrative policies. Budgeting. Monitoring operational trends. Problem solving. Planning a major capital investment. Approving board appointments. Evaluating CEO performance. Providing stewardship accountability to the sponsor. Managers, trustees, and sponsors may use information from the system to improve performance, shift strategy or revise major policies, and ensure continuity with the mission, philosophy, and traditions of the religious institute.

Aged↗
PubMedDate not supplied

Standardization and quality control for the determination of alpha-glucosidase in seminal plasma.

We attempted to provide an instruction for the standardization of alpha-glucosidase level determination and quality controls within the same laboratory and among different laboratories. Each of 51 semen samples was divided into two aliquots, centrifuging at 1000 g for 10 min or 3000 g for 15 min. The alpha-glucosidase level and sperm concentration of each sample were assayed. The alpha-glucosidase level in seminal plasma obtained at 3000 g for 15 min centrifugation was significantly lower than that at 1000 g for 10 min (p = 0.001). An additional 6 samples of seminal plasma with or without phenylmethylsulfonyl fluoride (PMSF), obtained at 3000 g for 15 min centrifugation, were frozen for 20 days, and each of 6 samples was determined for their alpha-glucosidase levels after thawing every other day. There was no significant difference between alpha-glucosidase levels in seminal plasma regardless of the presence of PMSF. The alpha-glucosidase level increased with the length of abstinence period. In conclusion, centrifugal velocity and abstinence time should be standardized in the alpha-glucosidase determination. Frozen seminal plasma may serve as the sample for quality control among clinical laboratories.

Centrifugation↗
PubMed2006

Quality control Fourier transform infrared determination of diazepam in pharmaceuticals.

A quality control procedure has been developed for the determination of diazepam in pharmaceuticals using Fourier transform infrared (FTIR) spectroscopy. The method involves the off-line extraction of diazepam with chloroform by sonication and direct determination in the extracts through peak area measurement in the interval between 1672 and 1682 cm(-1) using a baseline correction defined between 1850 and 1524 cm(-1). For standardization it was used an external calibration line established from standard solutions of diazepam in chloroform. The method provides a limit of detection of 0.04 mg per tablet (n=5), a relative standard deviation (R.S.D.) of 0.5% for 5 independent measurements of a standard solution at a concentration level of 0.76 mg g(-1) and a sampling frequency of the whole procedure of 4 h(-1), being required only 45 s for the measurement step. Results obtained by FTIR agree with those obtained by a reference methodology based on ultraviolet spectrometry and thus the developed procedure offers a good alternative for the determination of diazepam in pharmaceuticals.

Anti-Anxiety Agents↗
PubMed1995

Glycohemoglobin assays evaluated in a large-scale quality-control survey.

We report the results of a national quality-control survey on glycohemoglobin (GHb), monitored in France by the Société Française de Biologie Clinique on behalf of the authority of the "Agence du Médicament." A sample of lyophilized hemolysate was sent to 3109 laboratories. Results were obtained from 2770 laboratories. HbA1C, HbA1, and total GHb were measured by 50%, 24%, and 26% of the participants, respectively. Of these measurements, 79% of the HbA1C results and 76% of the total GHb results, but only 48% of the HbA1 results, were within the +/- 20% limits of the indicated target values. Mean values for the hemolysate ranged from 8% to 11% for HbA1C, from 7% to 12% for HbA1, and from 11% to 13% for total GHb. The interlaboratory CVs ranged from 3% to 20%, according to method used. So, methods used for GHb assay, which are based on various principles, exhibit very different analytical performances. Nonetheless, this large-scale study indicates that some techniques can support transferability of results from laboratory to laboratory.

Autoanalysis↗
PubMed1989

Quality control in immunohistochemistry. Report of a workshop sponsored by the Biological Stain Commission.

Although immunohistochemical methods are increasingly applied in diagnostic histopathology, there has been little standardization or quality control of immunoreagents; and published reports have not standardized Material and Methods for meaningful comparisons of results among clinicians. The Biological Stain Commission-sponsored workshop was convened to address the following issues: a manufacturers' testing program for probity of commercial antibodies, development of a manual for performance criteria and quality control assurance procedures, standardization of package inserts, standardization of information provided in the Materials and Methods sections of publications, establishment of a reagent and procedure clearing house, study of the effects of different fixation regimes on tissue antigens, and investigation of the environmental conditions needed for antigen-antibody interaction. The recommendations of the ad hoc committee and their implications for the future are discussed.

Antigen-Antibody Complex↗
PubMed2001

Evaluation of E test, disk diffusion and broth microdilution to establish tentative quality control limits and review susceptibility breakpoints for two aerobic actinomycetes.

A single laboratory study was carried out to compare E Test with broth microdilution and disk diffusion to establish tentative quality control ranges for Nocardia asteroides ATCC 19247 and Rhodococcus equi ATCC 6939 against a panel of eight antimicrobial agents. Reproducibility testing was performed on 12 consecutive days to establish tentative quality control ranges. A total of 36 clinical strains of the Nocardia asteroides complex and 5 Rhodococcus strains were used in the study. Both candidate control strains and clinical strains grew well on cation-adjusted Mueller-Hinton agar. Adequate growth occurred at 48 to 72 h for the Nocardia isolates and 24 to 48 h for Rhodococcus. A standardized primary inoculum of 5 x 10(4) CFU/mL was used for performance of E Test and disk diffusion for the Nocardia isolates. Tentative population-based error rates were calculated using current breakpoints for Enterobacteriaceae for E Test compared with disk diffusion for the 36 clinical strains of Nocardia species. Significant very major error rates were observed for imipenem (22%) and minor error rates varied from 2.7% to 50%. These methods require more extensive validation before definitive breakpoint criteria can be established.

Aerobiosis↗
PubMed1996

Ultrasound protocol and quality control procedures in the European Lacidipine Study on Atherosclerosis (ELSA).

The European Lacidipine Study on Atherosclerosis (ELSA) is a multinational interventional clinical trial aimed at determining the antiatherosclerotic effects of Lacidipine, a calcium antagonist, when compared to atenolol, a beta-blocker, on the carotid arteries of 2300 cardiovascular asymptomatic patients with moderately high blood pressure. Quantitative B-mode ultrasound imaging is being used to measure the intima-media thickness of a standardized section of the carotid arteries including the distal common, bifurcation, and proximal internal carotids. Prospective investigations of large samples of population using ultrasonographic endpoints rely heavily on the precision and reproducibility of the method. Therefore, specific quality control protocols are required to determine and monitor cross-sectional and longitudinal stability of the measurement reproducibility. In ELSA, the ultrasound methodology was specifically designed to include a set of procedures to quality control the critical components of measurement variation including instrumentation, and ultrasound operators, i.e. sonographers and readers. The ELSA clinical trial will provide the largest set of prospective quality control data on the use of quantitative B-mode ultrasound imaging.

Arteriosclerosis↗
PubMed1989

Choosing quality-control systems to detect maximum clinically allowable analytical errors.

Critical systematic and random analytical errors for 17 common clinical chemical components were estimated from published values for analytical imprecision, biological variation, and "medically important changes." Appropriate quality-control systems for these analytes are discussed on the basis of power considerations. The simple rule 1(3)s, with one control per run, is minimally sufficient for the analytes (about one quarter of those considered here) for which the magnitude of critical error is at least 3 analytical standard deviations. The more powerful rule 1(2)s, with one control per run, is the minimal requirement for analytes for which critical errors are about 2 analytical standard deviations; these are about half the remaining analytes. Greater power values are achieved by using multiple rules based on several controls per run. In general, this study does not support the view put forward by some authors that the quality-control rules in use today are too restrictive.

Chemistry, Clinical↗
PubMed1993

[Biological monitoring of lead: system and quality control].

The assessment of health effects of lead exposure is based on the determination of lead blood concentrations. The correctness of predicting these effects depends on the reliability of determination results. The latter can be confirmed only if the laboratory participates in the quality assurance programme for chemical analyses. The aim of the present study was to investigate the systems in use for quality control, methods of determining lead blood concentration and the results of a project on quality control for lead determination in Poland (project coordinated by the Nofer Institute of Occupational Medicine, Lodz, Poland). The paper discusses the principles of the quality assurance programme implemented in Poland, elements of good laboratory practice with respect to blood sampling, analytical equipment and the use of flameless AAS for determining lead blood concentration. The quality assurance programme for lead determinations covers nine laboratories. The initial stage of its implementation revealed that only 50% of the determinations were correct. Consequently, a series of audits was made at the laboratories and some training provided for the staff. The last round indicated an increase in the percentage of correct results of up to 80%. Proper performance of lead determinations carried out routinely for the assessment of industrial exposure to lead is of extreme importance in view of the fact that lead determinations in blood are planned to be made compulsory and to replace urinary determinations of the metal.

Environmental Exposure↗
PubMed1997

Strategies for reducing Papanicolaou smear screening errors: principles derived from data and experience with quality control.

A number of principles pertaining to types of measurements of Papanicolaou smear accuracy are presented and implications with respect to quality control operations are explored. There are strengths and weaknesses inherent in each of the quality control methods available to us; choices regarding which of them to use and specifics regarding their implementation should be guided wherever possible by common sense and well-analyzed data as well as by regulatory requirements. Definitions of error in particular require careful attention from the points of view of both microscopic criteria and choice of reporting nomenclature. Other elements that characterize Papanicolaou smear screening environments, such as workload limits and new technologies, are also discussed.

Diagnostic Errors↗
PubMed1995

GMP criteria for retest and failure analysis. Handling out-of-specification results in the pharmaceutical quality control laboratory.

The Food and Drug Administration's current Good Manufacturing Practices guidelines for the inspection of pharmaceutical quality control laboratories stress the need for explicit standard operating procedure's requirements for retesting criteria and the investigation of specification failures. Out-of-specification results are best handled through a priori procedures for the evaluation of their validity. These procedures should also specify the degree of retesting or resampling permitted. Initial investigations should focus on uncovering apparent laboratory-related or sampling errors. Should this initial investigation prove inconclusive, an expanded investigation should be conducted to uncover any less conspicuous cause, which could include process or operator-dependent as well as analytical errors. A schematic approach to controlling retesting through a rigorous policy of investigating failures, limiting retest analyses, and documenting and reporting all results is described.

Consumer Product Safety↗
PubMed2005

Quality control validation for exogenous natural surfactant labeled with 99mTc.

OBJECTIVE: Exogenous natural surfactant (ENS) labeled with 99mTc shows an elevated lung specificity allowing the acquisition of high-quality images for ventilation scintigraphy. METHODS: The methods for 99mTc-ENS quality control (physical properties, pH determination, radiochemical studies, and biologic studies) were evaluated and validated. RESULTS: The physical properties of the nonradioactive precursor and of the radiopharmaceutical were analyzed as general descriptors of the product. The pH of the radiopharmaceutical was determined by using pH test papers, a method described and validated in the United States Pharmacopeia. Chromatographic studies performed using the acetone/Whatman-1 paper system were validated as a method to evaluate the radiochemical purity of the 99mTc-ENS. Biodistribution studies on rats after intratracheal administration were validated as a method to estimate the radiopharmaceutical biodistribution in humans. CONCLUSION: The proposed method for 99mTc-ENS quality control studies and stability studies was evaluated and validated following international standards.

Animals↗