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PubMed1999

Test-retest reliability of psychological and neurobehavioral tests self-administered by computer.

A series of 12 psychological and 7 neurobehavioral performance tests were administered twice to a nonclinical normative sample with 1 week between administrations. The tests were presented in a self-administered computerized format. One week test-retest reliabilities were comparable to conventional administration formats. The results suggest that individual test reliability is not affected when tests are administered as part of an extensive multi-measure battery. Computer administered test reliability coefficients also were compared to a Mixed Format (computer-conventional) administration with mixed format reliabilities generally similar to the reliabilities of published conventional tests but also generally lower than same format testing. Compared to psychological test reliability, neurobehavioral test reliability appeared more vulnerable to decreases with mixed format testing. These conclusions should not be generalized to all computer implemented tests as the qualities of the test implementation will affect the outcome.

Adult↗

PubMed2004

The use of embryonic stem cells for regulatory developmental toxicity testing in vitro--the current status of test development.

The future chemical policy of the European Union as well as the 7th amendment of the cosmetic directive is calling for the development of alternative tests to animal experimentation for toxicological safety testing. In the field of embryotoxicity one of the most promising in vitro models are based on embryonic stem cells. The embryonic stem cell test has already been validated in comparison to in vivo results in an international blind collaboration study. The presented review is discussing the use, limitations and further needs for the test in order to be fully suitable for regulatory acceptance. In this context, it is summarized which requirements for an in vitro embryotoxicity test have to be fulfilled for regulatory toxicity testing. In addition, an overview about the current status of test development of other embryonic stem cell tests is presented. Several workshops have reviewed the progress of in vitro tests for developmental toxicity testing. A general consensus of these workshops has been that one single test will not be sufficient to cover all manifestations of developmental toxicity. The establishment of a test battery for developmental toxicity is required. This will be even more challenging since the principles of a composing test strategy and its validation have not been defined yet. Finally, the unique possibility of combining the human embryonic stem cell technology and the microarray techniques might lead to a deeper understanding of the toxicological mechanisms of human developmental toxicants.

Abnormalities, Drug-Induced↗

PubMed2004

[The comparison of the result of exercise bronchoprovocation test and methacholine bronchoprovocation test in athletes].

The excess contraction respond of the bronchiols to the specific and non-specific agent is called bronchial hyperresponsiveness. In our study we compared the result of exercise bronchoprovocation test and methacholine bronchoprovocation test in athletes (group I) and in sedentary subjects (group II). The subjects that their age, height, weight and environmental status of the test room (temperature and humidity) were not statistically different, they gave statistically different respond to the methacholine bronchoprovocation test (p< 0.05). Their respond to exercise bronchoprovocation test was similar and there was no statistically difference between two groups (p> 0.05). In group I, there was a correlation in the result of exercise bronchoprovocation test and methacholine bronchoprovocation test (r= 0.60, p< 0.05), but in group II there was no correlation in this two tests. The parameters that we use for evaluation of the allergic status (total IgE, eosinophil count, number of atopic subject in groups) were not statistically different (p> 0.05). In both two groups there was a statistically different respond in the result of exercise bronchoprovocation test and methacholine bronchoprovocation test. These findings suggests that methacholine bronchoprovocation test is a more sensitive test for the diagnosis of BHR in athletes and sedantery subjects than exercise bronchoprovocation test.

Adult↗

PubMed1997

[Comparison of a shuttle walking test with an exertion test with cycloergometer in patients with COPD].

To validate a shuttle walking test in a group of patients with COPD, comparing responses to those produced by a conventional stress test limited by symptoms on the cycle ergometer, and to analyze the relation between the shuttle walking test and maximal effort parameters. We enrolled 20 patients with COPD, mean age 60 years (SD 7), FEV1/46.6% (SD 19.2) of theoretical value and FEV1/FVC% 47.3% (SD 11.2). All the patients underwent a maximal effort test on the cycle ergometer, determination of initial dyspnea by applying Mahler's baseline dyspnea index, and a quality of life questionnaire specific to COPD the Chronic Respiratory Disease Questionnaire). To compare the responses of patients to the two tests, we analyzed heart rate, dyspnea and lactic acid at the end of each test. To see the relations between the two tests, we examined distance walked and maximal effort parameters. The relation between the walking test and lung function parameters at rest, initial dyspnea and quality of life were also analyzed. No statistically significant differences were found for heart rate [128.2 (SD 19.8) versus 131.6 (SD 12.9)], dyspnea 17.1 (SD 1.78) versus 7.24 (SD 2.64)] or lactic acid [5.24 (SD 2.34) versus 6.19 (SD 2.12)] at the end of the tests. Distance covered on the shuttle walking test correlated significantly with V'O2ml/min/Kgmax (r = 0.71), as well as with the remaining parameters of maximal effort. There was only a slight relation between lung function at rest and quality of life. The COPD patient's cardiovascular, metabolic and subjective responses to the shuttle walking test are similar to those of the cycle ergometer test, and oxygen consumption is significantly correlated. The shuttle walking test gives a valid estimate of the functional capacity of COPD patients.

Exercise Test↗

PubMed1990

Ergonovine maleate test detects anginal patients with poorly reproducible exercise tests.

The aim of the study is to evaluate the reproducibility of exercise testing and to determine whether there is any correlation between the reproducibility of exercise test and response to the ergonovine maleate test. Thirty-eight patients with mixed angina and documented coronary artery disease underwent an ergonovine maleate test and four exercise tests on consecutive days in the same basal conditions. The ergonovine test was positive in 20 patients (Group I) and negative in 18 patients (Group II). There were no significant differences in the clinical and angiographic data of the two groups. All 152 exercise tests were positive. The variability of the response of the repeated tests was assessed by means of an analysis of the following parameters: heart rate, blood pressure, rate-pressure product, watts, and minutes were recorded at the onset of ischemia (ST decreases greater than or equal to 0.1 mV). Range (maximal-minimal obtained value), ratio between range and maximal obtained value, and coefficient of variation (standard deviation/mean of the four parameters) were calculated for each patient. The analysis of these values demonstrated that while the test was reproducible in some patients, a high individual variability was present in others. Moreover, the individual variability results were higher in Group I than in Group II, with a statistically significant difference for all considered parameters. In conclusion, it is possible to have a poorly reproducible exercise test in patients with mixed angina. The correlation between a positive ergonovine test and a poorly reproducible exercise test suggests that abnormal coronary vasomotion may sometimes be present during exercise and may affect the reproducibility of the test.

Adult↗

PubMed2006

Impact of reflex HPV testing on interpretation and management of ThinPrep Pap tests.

HPV testing for high-risk types is the preferred method to triage women with atypical squamous cells (ASC) on ThinPrep Pap tests for management. The impact of this practice on the cytopathologists' interpretation is unknown. A significant percentage of providers at the Beth Israel Deaconess Medical Center (BIDMC) are not requesting reflex HPV testing. This offers a unique opportunity to examine its impact. Consecutive ThinPreps submitted to the cytology laboratory at the BIDMC for a 3-mo period were identified retrospectively. The ThinPreps were divided into those with a request for reflex HPV testing (reflex testing request group), those without such a request, and those with a request for HPV testing regardless of the diagnosis. Cytologic diagnoses, results of HPV testing and subsequent cervical biopsies within 6 mo after the ThinPrep were recorded and correlated in these cases. A total of 4,590 ThinPreps were processed during this period. 2,659 had a request for reflex HPV testing, 1,849 did not have such a request, and 82 had a request for HPV testing regardless of diagnosis. The numbers (%) of abnormal results in these three groups were 155 (5.8%), 141 (7.6%), and 22 (27%), respectively. The ASC:SIL ratios for these three groups were 1.2, 0.86, and 0.62, respectively. 38/71 (54%) women with ASC in the reflex testing request group were positive for high-risk HPV types. Of those with ASC in the reflex testing request and no request groups, 15/73 (21%) and 12/56 (21%) underwent biopsies with 2 (of 15) and 2 (of 12) showing HSIL on histology, respectively. Our study demonstrates that at our institution a request for reflex HPV testing did not significantly affect cytopathologists' interpretation of ThinPreps. Furthermore, HPV testing did not seem to have influenced the subsequent management of women with ASC diagnosis.

Biopsy↗

PubMed2003

Visual acuity testing in diabetic subjects: the decimal progression chart versus the Freiburg visual acuity test.

PURPOSE: To study reproducibility and biological variation of visual acuity in diabetic maculopathy, using two different visual acuity tests, the decimal progression chart and the Freiburg visual acuity test. METHODS: Twenty-two eyes in 11 diabetic subjects were examined several times within a 12-month period using both visual acuity tests. The most commonly used visual acuity test in Denmark (the decimal progression chart) was compared to the Freiburg visual acuity test (automated testing) in a paired study. RESULTS: Correlation analysis revealed agreement between the two methods (r(2)=0.79; slope=0.82; y-axis intercept=0.01). The mean visual acuity was found to be 15% higher (P<0.0001) with the decimal progression chart than with the Freiburg visual acuity test. The reproducibility was the same in both tests (coefficient of variation: 12% for each test); however, the variation within the 12-month examination period differed significantly. The coefficient of variation was 17% using the decimal progression chart, 35% with the Freiburg visual acuity test. CONCLUSION: The reproducibility of the two visual acuity tests is comparable under optimal testing conditions in diabetic subjects with macular oedema. However, it appears that the Freiburg visual acuity test is significantly better for detection of biological variation.

Adult↗

PubMed1990

An investigation of test-house variability in the mechanical testing of dental materials and the statistical treatment of results.

The suitability of a test for standard specification testing depends inter alia on the ability to repeat the tests in a reproducible manner at a number of test centres. This work involved the investigation of three tests currently proposed as standard specification tests for dental materials. It was found that one test (compressive strength of cements) is inappropriate for inclusion in standards due to an unacceptable variation in test results between test centres. The treatment of results suggested in standards should place less emphasis on the mean value of a relatively small number of test specimens and the use of a simple form of probability theory in which, say, 80 per cent of specimens are required to achieve a certain pass level. In some standards there may be a need to increase the numbers of test specimens significantly in order to achieve a more meaningful and reliable result. The use of Weibull statistics can be adopted as a means of identifying tests which are suitable for inclusion in standard specifications, although it is doubtful that a test at this level of sophistication is required or desirable for inclusion in the standards themselves.

Composite Resins↗

PubMed1994

Comparative evaluation of the E test for susceptibility testing of Nocardia species.

The E Test (PDM Epsilometer; AB Biodisk, Solna, Sweden) was compared with microbroth dilution and disk diffusion for antimicrobial susceptibility testing of Nocardia as a collaborative study by two geographically separate laboratories. A total of 52 clinical isolates and five species of Nocardia were used in this comparative evaluation. Susceptibility testing was performed with Mueller-Hinton media and eight antimicrobial agents. Growth of the test strains with Mueller-Hinton medium was generally satisfactory, with the majority of isolates producing adequate growth within 24-36 h. Growth inhibition ellipses were generally well delineated and uniform for most drugs, and the points of intersection with the E Test strip were generally easy to determine. An inoculum size of approximately 2.0 x 10(7) CFU/ml was optimal for performance of the E Test method with the Nocardiae. Comparison of E Test and microbroth dilution MICs revealed 89.4% agreement for all drugs within +/- 1 log2 dilution. Using NCCLS interpretive criteria for susceptible and resistant results, complete agreement between E Test and disk diffusion results was 93.3%, and between E Test and microbroth dilution results was 96.2%. Interpretive category errors occurred at rates of 18.2% (risk corrected), 0, and 4.1% for very major, major, and minor errors, respectively, when E Test results were compared with disk diffusion results, and 0, 0, and 3.8%, respectively, when E Test was compared with microbroth dilution. Inter- and intra-laboratory reproducibility, within +/- 1 log2 dilution for all drugs, was 95% and 98%, respectively. Results from this study suggest that E Test may be suited for use as an alternative method for antimicrobial susceptibility testing of Nocardia species.

Culture Media↗

PubMed2006

Characteristics of patients with abnormal glucose challenge test and normal oral glucose tolerance test results: comparison with normal and gestational diabetic patients.

OBJECTIVE: The purpose of this study was to evaluate the characteristics and outcomes of patients who had abnormal glucose challenge test results and subsequent normal oral glucose tolerance test results and to assess whether such patients are at a greater risk than normal pregnant patients for adverse perinatal outcome. STUDY DESIGN: In this retrospective cohort study that was conducted between June and December 2003, 101 pregnant women (group A) had an abnormal glucose challenge test result and a normal oral glucose tolerance test result. Data were also collected on 2 control groups: 100 pregnant women with normal glucose challenge test results (group B) and all 76 pregnant women who were diagnosed with gestational diabetes mellitus during this period of time (group C). Patients with multiple pregnancies, chronic hypertension, pregestational diabetes mellitus, or any other maternal or fetal problems that were diagnosed before 24 weeks (when the glucose challenge test was performed) were excluded from the study groups. The following data were collected and analyzed: maternal age, maternal weight and height, parity and gravidity, diabetes mellitus in first-degree relatives, medical and obstetric history, ethnicity, complications during the third trimester of pregnancy, birth weight, gestational age at delivery, mode of delivery, Apgar scores, cord blood gas results, maternal complications of labor and during the postpartum period, and infant admission to the neonatal intensive care unit. For comparison between groups, we used the Student t test, 1-way analysis of variance, the chi-square test, and stepwise logistic regression. RESULTS: Patients in groups A and C were significantly older compared with group B (29.2 +/- 5.6 years and 30.4 +/- 5.5 years, respectively, vs 24.8 +/- 5.5 years; P < .01), had a lesser rate of primiparity (48% and 31%, respectively, vs 24%; P < .05), had greater body mass index (30.8 +/- 5 kg/m2 and 31.3 +/- 6 kg/m2, respectively, vs 29.2 +/- 4.4 kg/m2; P < .01), had a greater rate of previous gestational diabetes mellitus (6% and 20%, respectively, vs 0%; P < .05), and had a greater rate of first-degree family members with diabetes mellitus (21% and 21%, respectively, vs 3%; P < .01). None of the outcome parameters was statistically significant when group A was compared with group B. CONCLUSION: Patients with an abnormal glucose challenge test result and a subsequent normal oral glucose tolerance test result have different maternal characteristics and backgrounds compared with patients in whom both test results are normal, yet both groups have normal outcomes. We should continue to consider patients who have an abnormal glucose challenge test result and subsequent normal oral glucose tolerance test result as low-risk; however, these findings may represent an indication of an increased likelihood for the development of overt diabetes mellitus later in life.

Adult↗

PubMed2000

Comparison of the monoclonal UBC-ELISA test and the NMP22 ELISA test for the detection of urothelial cell carcinoma of the bladder.

OBJECTIVES: To compare the diagnostic value of two enzyme-linked immunosorbent assay (ELISA) tests, the nuclear matrix protein 22 (NMP22) test and a newly developed urinary bladder cancer (UBC) test, in patients having symptoms suggestive of urothelial cell carcinoma (UCC) and patients under follow-up after transurethral resection (TUR). METHODS: Two hundred forty patients with a mean age of 65.8 years (range 22 to 92) were included in this retrospective study. The tests were performed on previously frozen urine samples. Eighty-one patients had symptoms suggestive of bladder cancer and 159 patients were being followed up after complete TUR of UCC. Voided urine was evaluated by the NMP22 test and the monoclonal UBC-ELISA test, which traces cytokeratins 8 and 18. All patients underwent subsequent cystoscopy and biopsy evaluation of any suspicious lesion. The cutoff levels for bladder cancer positivity were 10 U/mL for the NMP22 test and 12 microg/L for the UBC test. RESULTS: In the 54 patients with histologically proved UCC, the NMP22 test had a sensitivity of 55.5% and the UBC test a sensitivity of 64.8%. According to the histologic stages, the sensitivity of NMP22 was 51.7% in pTa tumors, 46.1% in pT1, and 70% in pT2 or higher tumors; the sensitivity of UBC was 62.1% in pTa, 53.8% in pT1, and 80% in pT2 or higher tumors. For histologic grades 1 to 3, the sensitivity was 50%, 50%, and 68.7% for NMP22 and 66.6%, 60%, and 68.7% for UBC, respectively. The specificity was 79% and 92% for NMP22 and UBC, respectively. CONCLUSIONS: The monoclonal UBC-ELISA test is superior to the NMP22 test in both sensitivity and specificity. Nevertheless, neither test can replace cystoscopy.

Adult↗

PubMed2006

Sensitivity and specificity of the agar-gel-immunodiffusion test, ELISA and the skin test for detection of paratuberculosis in United States Midwest sheep populations.

Our objective was to estimate the sensitivity and specificity of the agar-gel-immunodiffusion test (AGID), the ELISA, and the skin test for the detection of Mycobacterium avium subspecies paratuberculosis (MAP) in sheep using Bayesian methods without a gold standard. Fourteen flocks (2 465 sheep) were used. Five flocks (450 sheep) were considered MAP non-infected and 9 flocks (2 015 sheep) had sheep infected with MAP. Sheep were skin tested and blood was collected for AGID and ELISA testing. Results were analyzed using a Bayesian 3-test in 1-population model fitted in WinBUGS. The model allowed for dependence (correlation) between the two serologic tests, but these two tests were assumed to be conditionally independent of the skin test. The estimated specificity was 99.5% (95% PI of 98.9-99.9%) for the AGID; 99.3% (98.4-99.8%) for the ELISA using an optical density measured cutoff of 0.20; 99.2% (98.1-99.8%) using a cutoff of 0.15; 97.5% (95.8-98.7%) using a cutoff of 0.10; and 98.7% (97.3-99.5%) for the skin test. The estimated sensitivities were 8.3% (6.2-10.7%) for the AGID; 8.0% (6.0-10.4%), 10.6% (8.3-13.1%), and 16.3% (13.5-19.4%) for the ELISA using the cutoffs 0.20, 0.15, and 0.10 respectively; and 73.3% (62.3-85.8%) for the skin test. The skin test was specific in non-infected populations and sensitive in infected populations, although in some cases a positive skin test might represent MAP exposure rather than infection. The AGID and ELISA were specific but lacked sensitivity. The AGID and ELISA consistently identified two different populations of infected sheep with only moderate overlap between positive test results.

Animals↗

PubMed1998

Comparative clinical evaluation of the 13C-mixed triglyceride breath test as an indirect pancreatic function test.

BACKGROUND: Breath tests using stable isotopes of carbon or hydrogen are increasingly becoming established for the evaluation of various gastrointestinal functions, including measurement of exocrine pancreatic insufficiency. We wanted to evaluate the clinical relevance of the non-invasive, non-radioactive 13C-mixed triglyceride breath test in comparison with the secretin-caerulein test as the 'gold standard' of pancreatic function testing and with faecal chymotrypsin and elastase 1 in patients with mild and severe exocrine pancreatic insufficiency. METHODS: The secretin-caerulein test, faecal fat analysis, 13C-mixed triglyceride breath test, faecal elastase 1, and chymotrypsin and various morphologic investigations were done in 26 patients with mild (n = 13) or severe (n = 13) exocrine pancreatic insufficiency and 25 patients with gastrointestinal diseases of non-pancreatic origin. Twenty-seven healthy volunteers served as normal controls. After a 12-h fast 200 mg mixed triglyceride (1,3-distearyl,2(carboxyl-13C)octanoyl glycerol) were orally administered with a test meal, and breath samples were taken before and at 30-min intervals for 5 h thereafter, and the increase in 13C/12C isotopic ratio in breath was analysed by mass spectrometry. Various modifications of the test procedure were investigated. RESULTS: Specificity for impaired pancreatic function was higher for faecal elastase (90%) and equal for faecal chymotrypsin (82%) as compared with the various variables of the 13C-mixed triglyceride breath test (69-85%). The sensitivity of the 13C-mixed triglyceride breath test for total and separately for mild and severe exocrine pancreatic insufficiency was higher (total, 69-81%) than that of faecal chymotrypsin (total, 56%) but lower than faecal elastase (total, 92%). CONCLUSION: The 13C-mixed triglyceride breath test very sensitively reflects severe exocrine pancreatic insufficiency (steatorrhoea) but has limited sensitivity for the detection of mild cases. With regard to the higher sensitivity and specificity, the higher practicability, and the much lower cost, determination of faecal elastase 1 concentrations is superior to the 13C-mixed triglyceride breath test and therefore remains the most reliable indirect pancreatic function test available today.

Adult↗

PubMed1999

Specificity of human complement factor H-related protein test (Bard BTA stat Test).

OBJECTIVE: The Bard BTA stat Test is a new, rapid, non-invasive qualitative test that detects bladder tumour-associated antigen (human Complement Factor H-related protein) in urine. The objective of this study was to evaluate the specificity of the Bard BTA start Test in a healthy population. MATERIALS AND METHODS: Voided urine samples from 100 healthy volunteers were collected and tested using the BTA stat Test. In the case of a positive BTA stat result, i.v. urography, cystoscopy, ultrasound and-re-testing were performed and the BTA stat Test was repeated three months later. RESULTS: Two subjects tested positive by the BTA stat Test, but no bladder cancer was found. The specificity of the BTA stat Test in the studied healthy population was 98%. CONCLUSIONS: The BTA stat Test has very high specificity with a true test-dependent false-positive rate occurring in only 2% of the healthy population. These results justify further studies with the BTA stat Test for bladder cancer diagnosis, monitoring, and screening.

Adult↗

PubMed2004

Non-uptake of predictive genetic testing for BRCA1/2 among relatives of known carriers: attributes, cancer worry, and barriers to testing in a multicenter clinical cohort.

BRCA1/2 test decliners/deferrers have received almost no attention in the literature and this is the first study of this population in the United Kingdom. The aim of this multicenter study is to examine the attributes of a group of individuals offered predictive genetic testing for breast/ovarian cancer predisposition who did not wish to proceed with testing at the time of entry into this study. This forms part of a larger study involving 9 U.K. centers investigating the psychosocial impact of predictive genetic testing for BRCA1/2. Cancer worry and reasons for declining or deferring BRCA1/2 predictive genetic testing were evaluated by questionnaire following genetic counseling. A total of 34 individuals declined the offer of predictive genetic testing. Compared to the national cohort of test acceptors, test decliners are significantly younger. Female test decliners have lower levels of cancer worry than female test acceptors. Barriers to testing include apprehension about the result, traveling to the genetics clinic, and taking time away from work/family. Women are more likely than men to worry about receiving less screening if found not to be a carrier. The findings do not indicate that healthy BRCA1/2 test decliners are a more vulnerable group in terms of cancer worry. However, barriers to testing need to be discussed in genetic counseling.

Adult↗

PubMed2005

Course of contact allergy in consecutive eczema patients patch tested with TRUE Test panels 1 and 2 at least twice over a 12-year period.

Non-reproducibility of positive patch test reactions is common. In this retrospective study, we investigated the reproducibility of previously positive patch test reactions and the appearance of new positive reactions in a consecutive series of 264 eczema patients tested at least twice over a 12-year period using the TRUE Test standardized patch test system. Out of 297 positive reactions, 66% remained positive in a 2nd test, 10% were scored as doubtful and 24% as negative. Among the previously recorded doubtful reactions, 13% were positive in the 2nd test, 13% were again doubtful and 74% negative. In relation to the degree of patch test reactivity, 48% of the + reactions were reproducible, compared to 87% of ++ and +++ reactions. No difference in reproducibility was observed between patients tested with a short or a long-time interval between tests. With the use of the TRUE Test panels 1 and 2, methodological factors are minimized. The variation in patch test positivity may then be attributed to biological variation, which depends on several individual factors such as patch test reading, patient-related factors such as changed immunological sensitivity, regional variation of the skin on the back and the presence of more or less active dermatitis.

Allergens↗

PubMed1999

Comparison of agar dilution, microdilution, E-test, and disk diffusion methods for testing activity of cefditoren against Streptococcus pneumoniae.

This study evaluated the susceptibility of pneumococci to cefditoren by agar dilution and microdilution methods (both in air) and by E-test (AB Biodisk, Solna, Sweden) and disk diffusion methods (both in CO(2)). By the three MIC tests, the MICs at which 50 and 90% of isolates were inhibited (MIC(50)s and MIC(90)s) were, respectively, as follows (in micrograms per milliliter): for the 65 penicillin-susceptible strains tested, 0.016 and 0.03 (by agar dilution), 0.016 and 0.03 (by microdilution), and 0.016 and 0.03 (by E test); for the 68 penicillin-intermediate strains tested, 0.125 and 0.5 (by agar dilution), 0.125 and 0.5 (by microdilution), and 0. 25 and 0.5 (by E test); and for the 67 penicillin-resistant strains tested, 1.0 and 1.0 (by agar dilution), 0.5 and 1.0 (by microdilution), and 1.0 and 1.0 (by E test). With tentative cefditoren breakpoints (in micrograms per milliliter) of </=2.0 (susceptible), 4.0 (intermediate), and >/=8.0 (resistant), all strains were susceptible to cefditoren by agar, microdilution, and E-test results; with breakpoints of </=1.0, 2.0, and >/=4.0 microg/ml, 97% of strains were cefditoren susceptible by agar dilution results, 98% were susceptible by microdilution results, and 99% were susceptible by E-test results. When microdilution and E-test results were compared to those from the reference agar dilution method, 191 (95.5%) and 183 (91.5%) of strains gave essential agreement (+/-1 log(2) dilution); 8 (2.7%) minor discrepancies were found for both methods with a breakpoint of </=1. 0 microg/ml, and no discrepancies were found with a breakpoint of </=2.0 microg/ml. Disk test results (breakpoint, </=1.0 microg/ml) produced 2 major and 30 minor errors, with corresponding zone diameters (in millimeters) of >/=20 (susceptible), 17 to 19 (intermediate), and </=16 (resistant); a </=2.0-microg/ml breakpoint yielded zone diameters of >/=16 mm (susceptible). All three methods for testing the MIC of cefditoren showed excellent correlation.

Cephalosporins↗

PubMed2003

The World Health Organization's External Quality Assurance System Proficiency Testing Program has improved the accuracy of antimicrobial susceptibility testing and reporting among participating laboratories using NCCLS methods.

A total of 150 laboratories in 33 countries that followed the NCCLS testing procedures participated in the World Health Organization's External Quality Assurance System for Antimicrobial Susceptibility Testing (EQAS-AST) from January 1998 through March 2001. Laboratories tested seven bacterial isolates for antimicrobial resistance and reported the results to the Centers for Disease Control and Prevention (CDC) in Atlanta, Ga. The results were compared to the results generated at the CDC with the NCCLS broth microdilution and disk diffusion reference methods. Although there were few testing errors with Salmonella enterica subsp. enterica serovar Enteritidis, drugs that are not appropriate for therapy of Salmonella infections were tested and reported by 136 (91%) of 150 laboratories. In addition, 29 (20%) of 150 laboratories used the Staphylococcus aureus breakpoints to report oxacillin results for Staphylococcus saprophyticus. For a vanB-containing Enterococcus faecalis strain, 124 (83%) of 150 laboratories correctly reported vancomycin results that were +/-1 doubling dilution from the reference MIC or +/-3 mm from the reference disk diffusion result. Of the laboratories that tested Streptococcus agalactiae by disk diffusion, 17% reported nonsusceptible results for penicillin in error. While 110 laboratories (73%) tested the S. pneumoniae challenge isolate against a fluoroquinolone, 83% tested it against ciprofloxacin, for which there are no NCCLS interpretive criteria. Ten of 12 laboratories testing levofloxacin and 4 of 4 laboratories testing ofloxacin by an MIC method correctly reported resistant results for the isolate. Feedback letters sent to participating laboratories highlighted areas of susceptibility testing in individual laboratories that needed improvement. The positive impact of the feedback letters and the overall effectiveness of the EQAS program were documented in repeat testing challenges with pneumococci and staphylococci. The 31 and 19% increases in the numbers of laboratories using appropriate testing methods for pneumococci and staphylococci, respectively, in 2000 versus 1998 indicate that laboratory performance is improving.

Anti-Bacterial Agents↗