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PubMed2005

Evaluation and quality control of personal nephelometers in indoor, outdoor and personal environments.

Personal nephelometers provide useful real-time measurements of airborne particulate matter (PM). Recent studies have applied this tool to assess personal exposures and related health effects. However, a thorough quality control (QC) procedure for data collected from such a device in a large-scale exposure assessment study is lacking. We have evaluated the performance of a personal nephelometer (personal DataRAM or pDR) in the field. We present here a series of post hoc QC procedures for improving the quality of the pDR data. The correlations and the ratios between the pDRs and the collocated gravimetric measurements were used as indices of the pDR data quality. The pDR was operated in four modes: passive (no pump), active (with personal sampling pumps), active with a heated inlet, and a humidistat. The pDRs were worn by 21 asthmatic children, placed at their residences indoors and outdoors, as well as at a central site. All fixed-site pDRs were collocated with Harvard Impactors for PM2.5 (HI2.5). By examining the differences between the time-weighted average concentrations calculated from the real-time pDRs' readings and recorded internally by the pDRs, we identified 9.1% of the pDRs' measurements suffered from negative drifts. By comparing the pDRs' daily base level with the HI2.5 measurements, we identified 5.7% of the pDRs' measurements suffered from positive drifts. High relative humidity (RH) affected outdoor pDR measurements, even when a heater was used. Results from a series of chamber experiments suggest that the heated air stream cooled significantly after leaving the heater and entering the pDR light-scattering chamber. An RH correction equation was applied to the pDR measurements to remove the RH effect. The final R2 values between the fixed-site pDRs and the collocated HI2.5 measurements ranged between 0.53 and 0.72. We concluded that with a carefully developed QC procedure, personal nephelometers can provide high-quality data for assessing PM exposures on subjects and at fixed locations. We also recommend that outdoor pDRs be operated in the active mode without a heater and that the RH effect be corrected with an RH correction equation.

Air Pollutants↗

PubMed2004

Quality control and automation in cervical cytology.

Pap smear is a clinical screening test and does not have 100% sensitivity and specificity. Sensitivity of pap smear can be improved with proper collection techniques and education of all concerned. Implementation and maintenance of quality control measures help to detect, reduce and correct deficiencies in pap smear analysis. Advent of automated devices has provided an opportunity to further improve the sensitivity of pap smear. Automation in cytology, seemed wildly speculative a decade ago, is becoming a reality now. Areas of automation include: Data storage and retrieval by computers, automatic staining and coverslipping machines, sample preparation methods, screening process control-devices and imaging systems for searching and interpretation of abnormal cells.

Automation↗

PubMed1983

Medicaid program; reduction in error rate tolerance; Medicaid quality control program--HCFA. Final rule.

This final rule revises current Medicaid regulations by establishing new regulations concerning the disallowance of Federal financial participation to States whose eligibility payment error rate for Medicaid, as measured by the Medicaid quality control system, exceeds the 3-percent tolerance level. Specifically, this rule provides that the current regulations regarding the method of projecting anticipated error rates apply only to the period April 1, 1983 through December 31, 1983. This rule also establishes new regulations that apply to periods beginning January 1, 1984. These modifications to the regulations are based on and implement the provisions of section 133 of the Tax Equity and Fiscal Responsibility Act of 1982 (Pub. L. 97-248), which enacted section 1903(u) of the Social Security Act.

Centers for Medicare and Medicaid Services, U.S.↗

PubMed1979

Quality control of the latex-fixation test.

Standardization of the latex-fixation test for the detection of rheumatoid factor may be achieved by the preparation of a standard reference serum. A number of guidelines for the quality control of precision and sensitivity of the test are suggested. In the use of dilution procedures, a 0.1 log10 or a 0.05 log10 difference between tubes is employed. The end point is defined and titer expressed in terms of a final dilution represented by the amount of antigen-antibody added. For statistical purposes all serologic data are geometrically expressed. Commercial kits may be standardized in terms of minimum detectable units and normalized for titer and unit values to enable laboratories to compare results.

Humans↗

PubMed1995

[Quality control in pediatric radiology].

The authors recall the fundamentals of an adequate use of the X-rays considering to the ALARA (As Low As Reasonably Achievable) principle. The article deals more specifically with radiation protection and quality control in radiopediatrics, as this age group is essentially concerned with stochastic hazards, i.e. cancer induction and genetic injurious effects. The major elements of X-ray equipment are reviewed, including the X-ray generator, device, film-screen, radiogenic tube, automatic exposure device, and so on... The influence of technical parameters on dosimetry in terms of radiation protection as well as dosis variation, according to the type of disorder, are demonstrated. Reference is made to the radiologic techniques proposed by the Lake Starnberg Group.

Child↗

PubMedDate not supplied

100% rapid rescreening for quality assurance in a quality control program in a public health cytologic laboratory.

OBJECTIVE: To verij5 the efficacy of the quality control (QC) program in a cytologic laboratwy with a rapid rescreening (RR) protocol. STUDY DESIGN: RR, according to the Turret RR method, of all samples initially screened as negative at the Laboratory of Cytology, Adolfo Lutz Institute, was performed. The slides were reviewed for 60 seconds. Suspect smears were fully checked by 2 reviewers to determine the final diagnoses. A total of 2954 sequential cytologic results were considered in this study. Of the 2954, 2568 (86.9%) were considered initially negative according to our internal QC, and these cases underwent RR. Also, 10% were randomly selected from these negative cases for full reviewing. The internal QC in our laboratory includes review of cases selected according to clinical and cytomorphologic criteria. RESULTS: Among the 2954 total cases, QC detected 386 (13%) atypias with final diagnoses reported according to The Bethesda System 2001 as follows: 82 (2.18%) low grade squamous intraepithelial lesions (LSILs), 35 (1.18%) high grade squamous intraepithelial lesions (HSILs), 2 (0.06%) squamous cell carcinomas, 105 (3.5%) atypical cells of undetermined significance (ASC-US), 4 (0.12%) atypical endocervical cells (AECs) and 158 (5.3%) unsatisfactory samples. RR of 2568 smears initially considered negative selected 194 (7.5%) slides. Of the 194, 146 (75.3%) were negative, 28 (14.4%) ASC-US, 5 (2.6%) AEC, 1 (0.5%) LSIL and 14 (7.2%) unsatisfactory. Full review of a 10% random fraction of the 2568 cases interpreted as negative did not detect lesions but did detect 5 (1.95%) unsatisfactory samples. CONCLUSION: Internal QC used in our laboratory based on clinical and cytomorphologic criteria to select cases for review proved to be an efficient method of detecting HSIL and cervical cancer. The consensus basis of this program strongly limits the false positive and false negative rates and also provides subjects with continuing education. One hundred percent RR is more efficient than 10% full reviewing in detecting cervical abnormalities.

Brazil↗

PubMed2006

Fingerprinting quality control of Qianghuo by high-performance liquid chromatography-photodiode array detection.

A novel, simple and accurate fingerprint method was developed using high-performance liquid chromatography-photodiode array detection (HPLC-DAD) for the quality control of Qianghuo, a Tibetan folk and Chinese herbal medicine used as a diaphoretic, an antifebrile and an anodyne. For the first time, the feasibility and advantages of employing chromatographic fingerprint were investigated and demonstrated for the evaluation of Qianghuo by systematically comparing chromatograms of aqueous extracts with the professional analytical software recommended by State Food and Drug Administration (SFDA). Our results revealed that the chromatographic fingerprint combing similarity evaluation could efficiently identify and distinguish raw herbs of Qianghuo from different sources and different species. The effects on Notopterygium forbesii Boiss (Apiaceae) chromatographic fingerprints resulted from collecting locations, harvesting time were also examined.

Apiaceae↗

PubMed2005

Fingerprint quality control of Tianjihuang by high-performance liquid chromatography-photodiode array detection.

A novel, simple and accurate fingerprint method was developed using high-performance liquid chromatography-photodiode array detection (HPLC-DAD) for the quality control of Hypericum japonicum thunb (Tianjihuang), a Chinese herbal medicine used for the treatment of several bacterial diseases, infectious hepatitis, gastrointestinal disorder, internal hemorrhage and tumors. For the first time, the feasibility and advantages of employing chromatographic fingerprint were investigated and demonstrated for the evaluation of Tianjihuang by systematically comparing chromatograms with a professional analytical software recommended by State Food and Drug Administration (SFDA). Our results revealed that the chromatographic fingerprint combining similarity evaluation could efficiently identify and distinguish raw herbs of Tianjihuang from different sources. The effects resulted from collecting locations, harvesting time and storage time on herbal chromatographic fingerprints were also examined.

Chromatography, High Pressure Liquid↗

PubMed2002

Biosensors in fish production and quality control.

Fishery products are important not only from a nutritional point of view, but also as an item of international trade and foreign exchange earner for a number of countries in the world. Fish and shellfish are highly perishable, and prone to vast variations in quality due to differences in species, environmental habitats, feeding habits, etc. In addition, they can also function as carriers of several microbial and other health hazards. Therefore, maintenance of quality is of utmost importance in production and trade of fishery products. Most of the current quality control techniques are time consuming and cumbersome. There is an excellent scope for the application of biosensors in the seafood industry including the rapidly expanding aquaculture operations for fast assessment of quality. This article discusses the scope of applications biosensors in the seafood industry.

Animals↗

PubMed2006

Description and implementation of a quality control program in an imaging-based clinical trial.

RATIONALE AND OBJECTIVES: The American College of Radiology Imaging Network is participating in the National Lung Screening Trial, a large, multicenter, randomized controlled trial, comparing multidetector helical computed tomography (MDCT) versus chest radiography (CXR) in screening for lung cancer. Because the threshold for detection of disease is an inherent function of image quality, and consistent image quality is necessary to track changes in suspicious findings, our purpose was to develop an image quality control (QC) program across all clinical sites for both modalities. MATERIALS AND METHODS: The primary goals of the QC program include standardization of imaging protocols, certification of imaging equipment, and ongoing, periodic evaluation of the equipment calibration and image quality. Minimum standards for equipment and standardized cross-platform acquisition protocols are achieved via radiologist and physicist attestation forms and web-distributed technique charts, respectively. Imaging equipment performance standards are implemented through an initial machine certification process that includes equipment calibration. Ongoing assessment of equipment performance and calibration, as well as adherence to established imaging protocols. is accomplished via periodic submission of calibration records and phantom images. Participant-specific image acquisition parameters are entered into a web-based centralized database and variations from established protocols are automatically flagged for review. Participant radiation dose can be estimated from the image acquisition parameters applied to the imaging equipment calibration measurements. A radiologist visual review committee also evaluates participant images for diagnostic quality. Data are collected from 23 independent centers, representing 14 models of MDCT scanners from four manufacturers, and CXR systems that include film-screen, computed radiography, and direct digital radiography systems. RESULTS: Widespread imaging protocol variation in extant clinical practice-as well as variability in equipment technology, image acquisition parameters, manufacturer terminology, and user interface-have required careful standardization as a prerequisite to trial participation and ongoing image QC. Acceptable ranges for image acquisition parameters have been refined to accommodate continuously evolving equipment platforms and the scope of participant size and body habitus. CONCLUSION: Standardization of imaging protocols is a critical component of image-based clinical trials, predicated on ongoing dialogue between sites and a centralized review committee.

Artificial Intelligence↗

PubMed1999

Four-color CGH: a new method for quality control of comparative genomic hybridization.

Comparative genomic hybridization (CGH) has become a widely used method in molecular cytogenetics to screen for copy number aberrations in human malignancies. Although the hybridization protocol is relatively simple, the validation and quality control of CGH have remained difficult. We describe here a new modification of CGH, four-color CGH, which is based on conventional CGH with an added Cy5-labeled second reference DNA, that serves as an internal standard in every hybridization. The internal standard aids in identifying inconsistently hybridized chromosomal regions (such as 1pter, 19, 22). When using a special second reference DNA (from a sex-mismatched trisomy 13 cell line) for four-color CGH, it is possible to standardize the dynamic range of hybridization. The four-color CGH modification is simple to adopt, requiring only the addition of Cy5-labeled reference DNA to the existing hybridization protocol. The principles and the modifications of the CGH image analysis software are described in detail.

Breast Neoplasms↗

PubMed1980

Use of preserved organisms for individual test-use quality control of bacterial typing antisera.

Bacterial antigens representing 14 of the most common clinical isolates requiring serological confirmation for identification were prepared. These antigens were stable for periods in excess of 5 months, readily available, and sero-specific. Use of these antigens for quality control of bacterial typing antisera increased the accuracy, reduced the technician time, and obviated the delay which otherwise occurred while stock isolates were subcultured to provide a sero-specific control for this procedure.

Antigens, Bacterial↗

PubMed2002

Quality control materials for the determination of trace elements in airborne particulate matter.

The development of quality control materials for the determination of selected trace elements in air pollution studies is described. Three types of test samples were prepared for proficiency testing: (1) filters loaded with PM10 fraction of urban air particulate matter (APM) using high-volume air samplers, which were subsequently divided into smaller sections, (2) a bulk sample of APM collected in an automobile tunnel in Prague, and (3) simulated air filters loaded with APM using a wet deposition process. Homogeneity of the test samples was studied using instrumental neutron activation analysis, proton induced X-ray emission and atomic absorption spectrometry, and inductively coupled plasma optical emission spectrometry and mass spectrometry. Sufficiently homogeneous samples were prepared by all three procedures. The simulated air filters appeared to be the most suitable test samples for proficiency testing.

Journal Article↗

PubMed2005

Structural approaches to the study of oligosaccharides in glycoprotein quality control.

High-mannose-type oligosaccharides have been shown to play important roles in protein quality control. Several intracellular proteins, such as lectins, chaperones and glycan-processing enzymes, are involved in this process. These include calnexin/calreticulin, UDP-glucose:glycoprotein glucosyltransferase (UGGT), cargo receptors (such as VIP36 and ERGIC-53), mannosidase-like proteins (e.g. EDEM and Htm1p) and ubiquitin ligase (Fbs). They are thought to recognize high-mannose-type glycans with subtly different structures, although the precise specificities are yet to be clarified. In order to gain a clear understanding of these protein-carbohydrate interactions, comprehensive synthesis of high-mannose-type glycans was conducted. In addition, two approaches to the synthesis of artificial glycoproteins with homogeneous oligosaccharides were investigated. Furthermore, a novel substrate of UGGT was discovered.

Animals↗

PubMed1991

Investigations with enzyme-linked immunosorbent assays for Trichinella spiralis and Toxoplasma gondii in the Dutch 'Integrated Quality Control for finishing pigs' research project.

In the framework of the Dutch field trial 'Integrated Quality Control (IQC) for finishing pigs' ELISA (screening) techniques were used to detect animals seropositive for Toxoplasma gondii and/or Trichinella spiralis. The aim was to determine whether farms which consistently delivered seropositive pigs could be detected and monitored (defined as 'problem farms'). The investigation involved 120 farms and three slaughterhouses, and a total of 23,348 serum samples were examined. In addition, all pigs were also screened for the presence of Trichinella spiralis with the digestion method (pooled samples). The prevalence of seropositivity for Trichinella spiralis and Toxoplasma gondii was 0.3% and 2.1% respectively. Parasitological examinations concerning T. spiralis were negative. Considering the characteristics of the used methodology, the conclusion was drawn that there were no parasitological or serological indications for T. spiralis infections, and that with respect to T. gondii the infection rate seemed to be equally low for all farms involved. In addition, a longitudinal pilot study during a whole finishing period was undertaken at two finishing farms. Animals seropositive for Toxoplasma gondii were found from the earliest days of the finishing period. Housing and management may (still) play an important role in the prevention of contact with this parasite.

Abattoirs↗

PubMedDate not supplied

Search and destroy: ER quality control and ER-associated protein degradation.

Proteins synthesized in the endoplasmic reticulum (ER) encounter quality control checkpoints that verify their fitness to proceed in the secretory pathway. Molecules undergoing folding and assembly are kept out of the exocytic pathway until maturation is complete. Misfolded side products that inevitably form are removed from the mixture of conformers and returned to the cytosol for degradation. How unfolded proteins are recognized and how irreversibly misfolded proteins are sorted to ER-associated degradation pathways was poorly understood. Recent developments from a combination of genetic and biochemical analyses has revealed new insights into these mechanisms. The emerging view shows distinct pathways working in collaboration to filter the diverse range of unfolded proteins from the transport flow and to divert misfolded molecules for destruction.

Animals↗

PubMed1983

Medicaid program; reduction in error rate tolerance beginning October 1, 1983; Medicaid quality control program--HCFA. Proposed rule.

This proposed rule would revise current Medicaid regulations and establish new regulations concerning the disallowance of Federal financial participation to States whose eligibility payment error rate for Medicaid, as measured by the Medicaid quality control system, exceeds the 3-percent national standard. Specifically, the proposed rule would provide that the current regulations regarding the 3-percent national standard apply only to the period April 1, 1983 through September 30, 1983. The proposed rule would also establish regulations that would apply to periods beginning October 1, 1983. These modifications to the regulations are based on and implement the provisions of section 133 of the Tax Equity and Fiscal Responsibility Act of 1982 (Pub. L. 97-248).

Centers for Medicare and Medicaid Services, U.S.↗

PubMed1991

Interlaboratory variability in drug assay: a comparison of quality control data with reanalysis of routine patient samples. II: Digoxin. Clinical Pharmacology and Toxicology Study Group, Italian Society for Clinical Biochemistry.

Fifty-four laboratories providing a serum digoxin monitoring service participated in a 16-month prospective quality control (QC) study that involved (a) determination of spiked QC samples based on a human serum matrix and (b) reanalysis by two to four reference laboratories of patient samples randomly selected among those assayed routinely. Interlaboratory variability on spiked samples was limited, coefficients of variation being usually in the 11-21% range. Correlations between values reported by individual reference laboratories on routine samples were reasonably good irrespective of the techniques used, which were the enzyme-multiplied immunoassay technique (EMIT) or the fluorescence polarization immunoassay (FPIA). When all data were considered, the correlation between the original routine values and reference results (r = 0.93) was comparable to that observed for the other analytes (phenytoin and theophylline) included in the survey. When subsets of results were evaluated according to the technique used, the agreement between routine and reference results was good for samples originally measured by FPIA (r = 0.96), moderate for samples originally measured by non-EMIT/non-FPIA techniques (r = 0.92), and poor for the few samples originally measured by EMIT (r = 0.55). The poor correlation with EMIT results could be ascribed largely to erratic performance of two individual laboratories. It is concluded that interlaboratory variability in routine drug measurements is greater for digoxin than for other analytes such as phenytoin and theophylline, and that the analytical performance of some laboratories is grossly inaccurate.

Digoxin↗