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At least 91 records · Page 5Linked to original sources
PubMed1998

The Italian quality control study for evaluation of CD4 cells in centres involved in the treatment of HIV-1 patients. Italian CD4 Quality Control Group.

We report on the experience of establishing a national network for a quality control programme in evaluating CD4 cell counts in most Italian centres involved in the care of patients with HIV disease. The 68 centres were divided according to their geographical location into eight groups, and twice a year (tests A and B) they received three coded whole blood samples (two were replicates of the same sample) obtained from two informed HIV+ patients, one with CD4 counts/mm3 expected to be < 200 and one with values > 300. The medians of the determinations performed by the labs involved in each of the eight areas were taken as the 'true' values for each sample. Unsatisfactory performances for percentage of CD4 cells were identified as a CD4 analysis with residual values > or = +/- 5% and with deviates > or = +/- 2. For absolute numbers of CD4 cells, an unsatisfactory performance was defined as CD4 counts with residual > +/- 100 CD4 cells/mm3 and with deviates > or = +/- 2. The residual value is the CD4 value reported by each lab minus the median value. The deviate is the residual divided by the modified interquartile range (IQR x 0.75). Most of the centres provided reliable results. However, some labs failed to provide satisfactory results for percentages (6.25% of the tested labs for test A and 6.17% for test B) or absolute numbers (16.25% test A and 12.34% test B). Only 3.7% of the labs gave unsatisfactory results in both tests. Four of the unsatisfactory results from the two tests gave an error in absolute numbers > +/- 200 CD4 cells/mm3. Our data suggest that most Italian labs provide reliable results in evaluating the numbers of CD4 cells in HIV-1+ samples, but the importance of running a quality control programme is highlighted by our experience with those centres which provide unsatisfactory data which may lead to incorrect classification of the patients or assessment of treatment.

CD4 Lymphocyte Count↗
PubMed1996

Quality control of proliferation marker (MIB-1) in image analysis systems utilizing cell culture-based control materials.

Standard controls for quality control of cell growth (proliferation) assays in image analysis systems are not currently available. The authors have developed a system of controls, based on cultured and harvested human cell lines, that can mimic tissue sections. These controls help ensure quality control for the entire cell proliferation analysis process, from the initial cutting of the paraffin block through fixation, immunohistochemical staining, and interactive image analysis. The use of cell line controls is advantageous because of the greater cell population homogeneity and the volume of uniform slides that are obtainable, as opposed to the use of a heterogeneous tissue sample. This system provides an excellent means of evaluating the day-to-day performance of cell proliferation analysis and may also be adapted for use as a method of multi-institutional proficiency testing.

Biomarkers, Tumor↗
PubMedDate not supplied

[The SUVA (Swiss Accident Insurance Association) statistics and quality control].

Overall quality control in medicine takes place on various levels: Physician--Hospital--Insurer--Authorities, each having different requirements. Comparative standards are rather seldom. A model for a comparative standard for insurer purposes, the medical statistics package SUMEST' is presented. This model is diagnoses oriented and includes parameters for the severity of the accident, cost of treatment and treatment outcome, all based on 5-year data pool results.

Accidents, Occupational↗
PubMed1989

[Systematic assessment of postoperative complications. A form of personal quality control].

A quality control program for the surveillance of surgical complications is described which includes all persons working at a surgical unit. The house surgeon when writing his letter for the general practitioner after the patient is demissed uses a special form for postoperative complications. Ten well defined types of complications, e.g. haematoma, fistula, abscess, pneumonia are recorded. Another surgeon responsible for the control program gathers weekly all forms presenting the results monthly at an audit to all surgeons of the unit. Here results are discussed in detail. Each surgeon gets his own complication profile monthly. Every three months the results of surveillance program are presented to all staff members including nurses, so that cooperative actions to reduce the complication rate can be taken. From January 1, 1985 to June 30, 1987, 2597 operations were performed, 213 patients (8.2%) suffered postoperative complications especially after surgery of the colon and rectum (28%), cholecystectomy (26%) and hernia repair (18%). Comparing three time periods (1985, 86, 87) no significant amelioration of complication rates were found. But factors influencing complications like very high age of patients, seriousness of the disease, and diabetes were not evenly distributed in all three samples. Therefore it might be impossible to lower the complication rate since those factors can't be influenced by better preparation for and better performing of surgery.

Germany, West↗
PubMed1995

[Acute pericarditis--clinical quality control trial].

Quality control aims to analyze not only the results of therapy but the efficiency and cost effectiveness of diagnostic procedures. In a catamnestic analysis of the outcome in 97 patients with acute pericarditis seen at this hospital from 1982 to 1992, we tried to answer the question whether a conservative diagnostic strategy might harm the patient. The outcome in 33 patients after limited diagnostic activity (patient story, clinical status; WBC differential count, ESR; creatinine and creatine kinase; ECG and chest x-ray) was the same as in 33 patients who underwent additional diagnostic procedures. Moreover, in patients in whom after limited diagnostic activity the etiology of acute pericarditis (precordial pain and friction rub) remained unclear, additional diagnostic procedures did not settle the problem. We conclude that extensive and even invasive diagnostic procedures are justified in selected patients and in special circumstances only (fever > 38 degrees and protracted course of disease, marked pericardial effusion or threatening tamponade; epidemiological or scientific interest).

Acute Disease↗
PubMed1994

Use of combined Shewhart-CUSUM control charts in internal quality control of enzyme-linked immunosorbent assays for the typing of foot and mouth disease virus antigen.

An enzyme-linked immunosorbent assay (ELISA) for the typing of foot and mouth disease virus (FMDV) antigen was employed for the routine laboratory diagnosis of FMD at a regional veterinary laboratory in northern Thailand. An objective procedure was developed to monitor the test performance of the ELISA, using absolute test control limits in a Shewhart-CUSUM (cumulative sum) control chart method. The procedure detected significant data trends and 'beyond control limit' situations for each antigen typing system (types O, A and Asia 1), using an assay variable (gamma i). Retrospective analysis using Shewhart-CUSUM control charts of data from 42 ELISAs demonstrated that control limits were exceeded in two assays for FMDV type A. The Shewhart-CUSUM control chart is a simple and reliable internal quality control method for the detection of significant random and systematic variation in assays.

Animals↗
PubMed1979

Suitability of commercial control sera for the quality control of activity determination of alkaline phosphatase.

The suitability of thirteen commercially available control sera for measuring alkaline phosphatase (EC 3.1.3.1; orthophosphoric acid monoester phosphohydrolase, ALP) activity in human serum was tested. Apart from differences in ALP activity observed in some reconstituted commercial sera, the behaviour of control materials towards experimental variables such as the nature and concentration of the substrate, pH and type of buffer (or PO4-acceptor) together with the composition of the isoenzymes present in human serum highlights the problems and difficulties if commercial materials are to be used as control sera. The half-saturation constants in control sera were in all cases smaller than those of ALP isoenzymes from bone and liver. The shape of substrate activity curves and the pH optimum in most of control sera differed from that of human serum. The discrepant kinetic data of control materials and human serum may mask or suggest changes relevant to commercial quality control serum but not to samples of human serum.

Alkaline Phosphatase↗
PubMed1997

In vitro antimicrobial activity and MIC quality control guidelines of RPR 106972 (RPR 112808/RPR106950): a novel orally administered streptogramin combination. The Quality Control Study Group.

RPR 106972 is a novel oral streptogramin combination with reported therapeutic potency against Gram-positive and certain respiratory tract pathogens. MICs for RPR 106972, quinupristin/dalfopristin, and seven comparison drugs were determined by the reference methods against 337 strains selected to define spectrum and potency. RPR 106972 demonstrated antimicrobial activity against oxacillin-susceptible and -resistant Staphylococcus aureus (MIC ranges of 0.12 to 2 micrograms/ml and 0.5 to 2 micrograms/ml, respectively), and coagulase-negative staphylococci were also inhibited by RPR 106972 (MIC90, < or = 0.5 microgram/ml) and quinupristin/dalfopristin (MIC90, < or = 0.25 microgram/ml). Against all streptococcal strains tested (including penicillin-resistant pneumococcus), RPR 106972 was highly active with MIC results at < or = 1 microgram/ml. RPR 106972 inhibited Corynebacterium jeikeium (MIC90, 0.5 microgram/ml). Moraxella catarrhalis (MIC90, 0.25 microgram/ml), and some Haemophilus influenzae (MIC50, 2 micrograms/ml). RPR 106972 and quinupristin/dalfopristin demonstrated little activity against Enterococcus faecalis (MIC90s, 4 to 32 micrograms/ml) as compared to Enterococcus faecium (MIC90s, 0.5 to 1 microgram/ml) and other Enterococcus ssp. (MIC90s, 1 microgram/ml). Studies to establish MIC quality-control guidelines indicated the following ranges: for E. faecalis ATCC 29212, 0.5 to 4 micrograms/ml; for S. aureus ATCC 29213, 0.25 to 1 microgram/ml; and for Streptococcus pneumoniae ATCC 49619, 0.06 to 0.5 microgram/ml. The results of this study indicate that the in vitro activity of RPR 106972 against Gram-positive bacteria and selected Gram-negative respiratory organisms is promising and warrants additional studies of pharmacokinetics, and in vivo infection model dynamics.

Administration, Oral↗
PubMed1983

Stability test of six enzymes for internal quality control.

The daily quality control for the determination of the catalytic activity concentrations of enzymes is an important aspect in clinical chemistry. Instead of the expensive, commercially available control sera, we have looked for a simple, reliable and cheap method for the quality control of enzyme determinations. Commercially available enzymes were suspended in an albumin solution and ampoules were filled with 1.0 ml of these various solutions. The ampoules were stored at 4 degrees C or -20 degrees C. Once a week, during 10 months, catalytic activities of these enzyme-albumin solutions were determined together with the same activities in freshly reconstituted control sera. Aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatine kinase and gamma-glutamyltransferase were determined at 30 degrees C according to well-described methods. alpha-Amylase was determined with the Phadebas method at 37 degrees C. Except for creatine kinase, the stability and reliability of these enzyme solutions are fully comparable with control sera during the experimental period. The catalytic activity concentration of creatine kinase decreased slowly during the 10 months. The enzyme solutions react in the same manner as commercial test sera on changes in the reaction conditions for the enzyme determinations. The conclusion seems justified that these enzyme solutions can be used for the daily quality control of the enzyme determinations instead of control sera.

Alanine Transaminase↗
PubMed1983

[Evidence of improved quality of urinary calculus analysis using results of 7 surveys with external quality controls. Improvement in the quality of urinary calculus analysis by establishment of uniform methodological assumptions in urinary calculus analysis laboratories. 2].

Seven quality control surveys confirmed the usefulness of standardized urolith analysis by X-ray diffraction. A method is suggested for tabulating the results of the surveys, which permits qualitative comparison of participating analysis centres. Quality improved considerably after the introduction of the standardized instructions for analysis. The results of the survey with international participants clearly demonstrated the superiority of X-ray diffractometric urolith analysis over polarization microscopical, infrared spectroscopic, differential thermoanalytical and wet chemical analytical techniques.

Humans↗
PubMed1976

On the design of clinical chemistry quality-control sera.

Quality-control specimens having quantitave interspecimen relationships were prepared by (a) making admixtures of two serum pools and (b) making various dilutions of the admixtures. The specimens were analyzed for many constituents to illustrate how the data obtained could be manipulated and used. The inter-related specimens permit the reduction of quality-control data to a few target values and should be particularly useful for the evaluation of multi-channel analyzers, and for use in inter-laboratory proficiency surveys. Aspects of the design of quality control and proficiency test specimens are also discussed.

Alkaline Phosphatase↗
PubMed1992

Development of revised quality control limits for disk diffusion susceptibility tests of selected cephem antibiotics with Haemophilus influenzae and description of a new control strain.

Inconsistent quality control results in disk diffusion testing of cefaclor, cefamandole, cefonicid, and cefuroxime with Haemophilus influenzae ATCC 49247 and Haemophilus test medium (HTM) prompted a search for an alternative control strain that would provide more reliable results. A five-laboratory study was conducted to evaluate two candidate H. influenzae strains as possible alternatives to the aforementioned strain. Repetitive testing of the candidate strains and H. influenzae ATCC 49247 over several days with a total of six different lots of HTM documented consistent performance of the two candidate strains and confirmed inconsistent results for some of the antibiotics with H. influenzae ATCC 49247. In particular, certain lots of HTM failed to yield cefaclor and cefamandole zone sizes within the quality control range advocated by the National Committee for Clinical Laboratory Standards. Because of the greater consistency offered by the new strains, one was selected (now designated H. influenzae ATCC 49766) to be recommended for routine quality control testing of cefaclor, cefamandole, cefonicid, cefuroxime, and the related carbacephem loracarbef. The new control strain and zone size ranges proposed here have been approved by the National Committee for Clinical Laboratory Standards in place of the previously recommended strain and zone size limits for testing of these five cephem antibiotics.

Ampicillin↗