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PubMed1996

The flashlight test and van Herick's test are poor predictors for occludable angles.

OBJECTIVE: To determine the reliability and validity of the flashlight test and van Herick's test in detecting occludable anterior chamber angles. METHODS: The flashlight test, van Herick's test and gonioscopy were performed independently by two observers on 96 consecutive new patients in our outpatient clinic. Interobserver agreement was determined using the weighted Kappa statistic. Using the glaucoma specialist's assessment of occludability of the angle (assessed by gonioscopy) as a gold standard, the sensitivities and specificities of the two tests were calculated. RESULTS: All three tests showed good agreement (Kappa more than 0.75). The sensitivity and specificity on the flashlight test were 45.5% and 82.7% respectively. For the van Herick's test they were 61.9% and 89.3%. CONCLUSION: The flashlight test and van Herick's test are of limited use as screening tests for occludable angles.

Adolescent↗

PubMed1978

Testing for food allergy: a statistical comparison of cytotoxic and intracutaneous tests.

This study presents a comparison of in vitro cytotoxic food allergy test results with those of in vivo intracutaneous food allergy testing by both objective serial dilution titration and subjective provocation. During the study the cytotoxic test was utilized as a screening device for follow-up Lee intracutaneous testing, the latter providing statistics for both noted in vivo intracutaneous tests. The study is presented in two stages. The first stage documents almost 6000 comparison test results on 300 consecutive food-allergic otolarynogology patients. Thirty-four of the more frequently offending foods were utilized. Of the cytotoxic tests, 86% resulted in positive reactions. Of the positive cytotoxic reactors, 74% were intracutaneously re-checked. Only those negative cytotoxic reactors suspected of false negativity were so challenged, affording comparison statistics for a smaller 21% of the negative reactors. Poor correlation statistics for this select negative reacting group prompted a follow-up 30-patient study on 11 foods that appeared to possess a lesser potential for hypersensitivity production. The second stage emphasizes similar test comparisons on the negative cytotoxic reactors. The study concludes that no correlation exists between in vitro cytotoxic test determinations and those of in vivo intracutaneous testing by objective serial dilution titration or subjective provocation. Because most allergic individuals have multiple food allergies, clinical success utilizing the information obtained from any or all of these procedures may rely significantly on the tests' inherent tendency to identify multiple guilty foods for ultimate treatment.

Cytotoxicity Tests, Immunologic↗

PubMed1998

International standards for test methods and reference sera for diagnostic tests for antibody detection.

International standards are necessary to ensure that the diagnostic tests used by trading partners meet a minimum standard of diagnostic performance. The tests that are used to qualify animals for international movement must provide a degree of confidence that those animals which give negative test results (and therefore qualify for movement) are free of a particular infectious disease agent. Without the development of standards for diagnostic tests, no level of international harmonisation can ever be achieved. International standards for both test methods and sera serve to establish a baseline on which inferences can be made with respect to the diagnostic performance of a given test in a given laboratory. International standard test methods set baseline analytical and diagnostic performance requirements for new reagents or methodologies. International standard sera are primary reference standards and serve as both reference materials for the calibration of test methods and reagents and prototypes for the production of national and working standards. For most serological test methods, three standard sera should be established: a strong positive, a weak positive and a negative standard. These standards are used to calibrate the detection range and analytical sensitivity of the test method. Assays calibrated in this way are more likely to exhibit a diagnostic sensitivity and specificity which parallels that of the standard test method, thus resulting in a higher degree of international harmonisation.

Animals↗

PubMed2005

Inventions leading to the development of the diagnostic test kit industry--from the modern pregnancy test to the sandwich assays.

The universities are encouraged by the government nowadays to stimulate innovations and also to provide the proper machinery for assisting the protection and commercialisation of innovations. A better understanding of the innovation process may help to create an atmosphere suitable for inventions at the university. Examples can be taken from successful innovations previously made at the university. During the 1960's I made a series of inventions, which ultimately led to the development of the diagnostic test kit industry. The first, which I made as an undergraduate, was a simple and reliable test kit for diagnosis of pregnancy. This was followed by the solid phase radioimmunoassay and a solid phase assay for vitamin B12; next, the dual specific non-competitive sandwich assay and the in-vitro test for diagnosis of allergy, called RAST (Radioallergosorbent test). Organon in Holland with the pregnancy test kit, and Pharmacia in Sweden with test kits for radioimmunoassay, became pioneers among the diagnostic test kit industries. Pharmacia Diagnostics later became one of the leading diagnostic test kit companies in the world and has continued to be so in the field of allergy diagnosis. Each one of these inventions started with a few unique observations leading to a technical development. The pregnancy test as well as the allergy test emerged from the development of assay methods with unique qualities with the subsequent search for appropriate applications. The foreseeing of a commercial value on a future market was a very important step. This was followed by the search for a suitable industry interested to exploit the invention with its new business opportunity i.e. apply for a patent, produce and market the products, which in my case consisted of the necessary reagents and equipments for particular diagnostic tests. Finally, an agreement had to be settled between the entrepreneur and the inventors. This report describes these inventions and particularly discusses some crucial steps of the innovation processes.

Binding, Competitive↗

PubMed2004

[Study on the use of haemoglobin denaturation test as an alternative to Draize eye irritation test].

OBJECTIVE: To use haemoglobin denaturation test (HD test) as an alternative to Draize eye irritation test (Draize test). METHODS: Fourteen cosmetic ingredients were tested by HD test. The results were compared with two kinds of scores in Draize test, i.e. Maximum average Draize total score (MAS) and Score of 24 h after application (S24). RESULTS: The correlation coefficient between RDC50 and MAS and that between RDC50 and S24 were 0.926 and 0.921 respectively, while that between 1%lambdamax and MAS, and between 1%lambdamax and S24 were 0.881 and 0.791 respectively. The results showed that RDC50 had a higher correlation with Draize test than 1%lambdamax did, but in the use of RDC50 some information of data would be lost. On the other hand, 1%lambdamax, which had a greater correlation with corneal score in the three component scores of the Draize test, could be used for assessing water-insoluble chemicals. CONCLUSION: The results showed that HD test could be used as an effective alternative to Draize eye irritation test.

Animal Testing Alternatives↗

PubMed1992

Results of the National Institute of Allergy and Infectious Diseases Collaborative Clinical Trial to test the predictive value of skin testing with major and minor penicillin derivatives in hospitalized adults.

BACKGROUND: A history (or lack thereof) of penicillin allergy is known to be unreliable in predicting reactions on subsequent administration of the drug. This study tests the usefulness of four penicillin allergen skin tests in the prediction of IgE-mediated reactions subsequent to administration of penicillin. METHODS: Eight centers cooperated in the National Institute of Allergy and Infectious Diseases trial of the predictive value of skin testing with major and minor penicillin derivatives. Hospitalized adults were tested with a major determinant (octa-benzylpenicilloyl-ocytalysine) and a minor determinant mixture and its components (potassium benzylpenicillin, benzylpenicilloate, and benzylpenicilloyl-N-propylamine). Patients then received a therapeutic course of penicillin and were observed, for 48 hours, for adverse reactions compatible with an IgE-mediated immediate or accelerated allergy. RESULTS: Among 726 history-positive patients, 566 with negative skin tests received penicillin and only seven (1.2%) had possibly IgE-mediated reactions. Among 600 history-negative patients, 568 with negative skin tests received penicillin and none had a reaction. Only nine of the 167 positive skin test reactors received a penicillin agent and then usually by cautious incremental dosing. Two (22%) of these nine patients had reactions compatible with IgE-mediated immediate or accelerated penicillin allergy; both were positive to the two determinants. CONCLUSIONS: These data corroborate previous data about the negative predictive value of negative skin tests to these materials. The reaction rate in skin test-positive patients was significantly higher than in those with negative skin tests, demonstrating the positive predictive value of positive tests to both major and minor determinants. The number of patients positive only to the major determinant or only to the minor determinant mix was too small to draw conclusions about the positive predictive value of either reagent alone.

Adult↗

PubMed1978

Comparison of a leucocyte adherence test with the leucocyte migration inhibition test and skin reactivity to PPD.

Using PPD as antigen, a leucocyte adherence test was compared with the leucocyte migration inhibition test and with the results of skin testing in healthy subjects. In the presence of antigen, leucocyte adherence was significantly greater in skin test-positive subjects than in skin test-negative subjects who had not previously had BCG vaccination. When the test was performed in heterologous serum, skin test-negative subjects who had had previous BCG vaccination showed significantly greater leucocyte adherence in the presence of antigen than skin test-negative subjects who had not had BCG vaccination; this difference was not present in autologous serum and its abolition was attributed to a serum blocking effect. The leucocyte adherence test correlated with the results of the leucocyte migration inhibition test in heterologous serum, and also with the results of skin testing interpreted in the light of previous vaccination history. The finding of increased rather than decreased adherence in the presence of antigen, although previously reported, is unusual.

BCG Vaccine↗

PubMed1993

13C-labeled trioctanoin breath test for exocrine pancreatic function test in patients after pancreatoduodenectomy.

To assess exocrine pancreatic function in patients before and after pancreatoduodenectomy (PD), we used the breath test, with nonradioactive 13C-labeled trioctanoin, in 14 patients before pancreatic resection because of localized pancreatic mass (preop-PD group), and in 13 patients who had undergone pancreatoduodenectomy more than 5 yr before (post-PD group). The results were compared with those of the secretin test, N-benzolyl-L-tyrosyl-p-amino benzoic acid (BT-PABA) test, and fecal chymotrypsin. Means +/- SD and frequencies of low values of the recovery of the breath test were 42.0 +/- 3.4%, 0/5 in the control; 24.2 +/- 10.5%, 14/14 in the preop-PD group; and 18.6 +/- 8.0, 13/13 in the post-PD group. The overall sensitivities in the preop- and post-PD groups were 100% for the recovery and 93% for the maximal mass ratio of the breath test, 89% for the secretin test, 67% for the BT-PABA test, and 64% for fecal chymotrypsin. The recovery of the breath test correlated significantly with the duodenal outputs of lipase, amylase, and chymotrypsin, and was not affected in patients with obstructive jaundice or with low D-xylose absorption. The breath test is as sensitive as the secretin test, more reliable than the conventional tubeless tests, and is available to follow up the exocrine pancreatic function before and after pancreatoduodenectomy.

4-Aminobenzoic Acid↗

PubMed1993

[Comparison of food specific IgE antibody test (RAST) and skin tests in children with atopic dermatitis].

Thirty children with atopic dermatitis were enrolled in our study to evaluate the food specific IgE antibody assay (RAST) and skin tests as a screening test for food hypersensitivity. Our results showed that eight food antigens (fish, shrimp, crab, soybean, milk, egg-white, peanut, wheat) frequently elicited positive hypersensitivity reactions. Twenty-four patients had at least a positive skin reaction to one of the foods tested. Of the 240 skin tests, 30% (72/240) yield positive reactions. Eighteen patients had at least a positive RAST reaction to one of the foods tested, 20.9% (50/240) yield positive reaction. The agreement between skin test and RAST was 79.6%. Crab and shrimp accounted for most frequent positive reaction in both tests. The skin tests produced more positive results in skin testing than RAST, but gave a higher frequency of false positive results. The diagnosis of food allergy may be suspected from the medical history or by food specific IgE antibodies together with skin test as a screening test. Furthermore, the double blind placebo controlled food challenge should be considered as standard for clinical investigations.

Adolescent↗

PubMedDate not supplied

Relationship between two dichotic listening tests and the Token test for children.

The relationship between two dichotic listening tasks was studied. The two dichotic tests used were the Staggered Spondaic Word (SSW) test and the directed Dichotic Consonant-Vowel (CV) test. These measures were administered to 104 children between the ages of 6.0 and 8.0 yrs. The subjects were divided into two groups according to their Token test scores with group I having normal Token test scores and group II having below average scores on the Token test. When the performances of the two groups on the SSW test were compared, a significant difference was found between them on the right and left competing conditions of the test. There was no difference between the groups on any response bias. On the directed Dichotic CV test the two groups were significantly different on the right ear scores but not on the left ear scores under both directed conditions. The groups were also significantly different on the directed right task when the difference between the two ear scores was compared but not on the directed left task. It was concluded that there is a relationship between these two dichotic measures and the Token Test for Children.

Auditory Pathways↗

PubMed1990

A clinical study of the automated assessment of intelligence by the Mill Hill Vocabulary test and the Standard Progressive Matrices test.

As part of the Leicester/DHSS project on microcomputer-aided assessment, 274 patients at five clinical sites were assessed with either a computerized version or the standard version of the Mill Hill Vocabulary (Synonyms) test. Of this group, 178 were retested on the alternative version of the test. Similarly, 184 patients were tested with either a computerized version or the standard version of the Standard Progressive Matrices test, of whom 129 were retested on the alternative test form. High correlations were found between the standard and computerized versions for both tests. For the Mill Hill Vocabulary test, no significant difference was found between test versions for first administration, and the vast majority of retested subjects had very similar scores on each version. On the Standard Progressive Matrices, however, subjects obtained significantly lower scores on the computerized test. It is concluded that whereas the computerized Mill Hill Vocabulary test could be used in place of the standard version of clinical settings, the computerized Standard Progressive Matrices test could not be used.

Adolescent↗

PubMed1996

Laboratory tests as predictors of disease exacerbations in systemic lupus erythematosus. Why some tests fail.

OBJECTIVE: To evaluate whether changes in laboratory test values are either simultaneous with or precede disease exacerbations in patients with systemic lupus erythematosus (SLE). METHODS: At 9, 6, and 3 months preceding a flare in disease activity (defined as a rise of > or = 6 points in the modified SLE Disease Activity Index), laboratory tests were performed to measure patients' hematocrit levels, white blood cell, lymphocyte, and platelet counts, erythrocyte sedimentation rate, C1q binding, DNA binding, and levels of C3 and C4. Flares were classified as either present or absent, and were divided into renal, vasculitic, central nervous system, skin, serosal, and musculoskeletal subgroups. The predictive patterns were 1) the simultaneous change in the test value from the mean of 9, 6, and 3 months preceding a flare to the time of the flare; 2) the gradual change, following a linear time trend, in test results for the same time points; and 3) the change from the mean of 9 and 6 months to 3 months preceding a flare, as a measure of predictive ability. These analyses used repeated-measures analysis of variance models. Multiple linear regression was used to study the cross-sectional association of average-over-time differences in test results with patients' flare subgroup. RESULTS: Among 202 patients with SLE (median followup 86.5 months), 83 flares occurred in 53 patients. Of 189 statistical contrasts performed, only 14 were significant (versus 10 expected), and the differences were of minor importance. Nonetheless, evaluation of all test results over each patient's observed disease course revealed significant differences between selected test values in association with specific types of flare. CONCLUSION: Fluctuations in laboratory test values are poor predictors of disease exacerbations in SLE. Cross-sectional evaluation of some test results revealed differences at the time of flare for those patients who were destined to have different types of flares, because these values differed over the entire study period. This pattern explains the frequent cross-sectional association of disease activity with laboratory test results, and the inconsistent association of flares with recent changes in test values.

Adolescent↗

PubMed2002

Analytic methods for comparing two dichotomous screening or diagnostic tests applied to two populations of differing disease prevalence when individuals negative on both tests are unverified.

Two dichotomous screening tests may be compared by applying both tests to all members of a sampled population. For individuals with a positive result on either test the disease status may be verified by a reference standard, but for individuals negative on both tests the disease status may be unverified because the probability of disease is so low that further investigation is costly, unacceptable and perhaps unethical. If the tests have been applied to samples from two populations which have different disease prevalences then unbiased estimates of the true positive and false positive rates of each test, the prevalences in the two populations, and two parameters representing dependence between the two tests can be estimated using maximum likelihood methods. The methods are based on the assumption that the sensitivities and specificities of the two tests, and the dependencies between the tests, are independent of prevalence. A test of goodness of fit provides a test of this.

Adult↗

PubMed1989

A differentiated approach to testing skin sensitization. Proposal for a new test guideline skin sensitization.

The present EEC and OECD Guidelines for testing skin sensitization have been reviewed in light of scientific evidence demonstrating that those methods which use Freund's Complete Adjuvant (FCA) are likely to be more accurate in predicting a probable skin-sensitizing effect of a new substance in humans than those methods not employing Freund's Complete Adjuvant. In this new test guideline, therefore, the primary testing of a substance should be carried out using one of the recommended Adjuvant methods. In special cases a non-adjuvant method may be performed in addition. Not all of the seven methods in the EEC Guideline or eight methods in the OECD Guideline have been included, but in a proposal for an updated test protocol two Adjuvant tests (Maximization test by Magnusson and Kligman and Optimization test by Maurer), and two non-Adjuvant tests (Open Epicutaneous test by Klecak and Buehler test) are suggested. The criteria for selecting these methods are based on the fact that they are well validated and widely used on a broad basis by the scientific community. Furthermore, it is considered appropriate to permit the use of a lower number of animals than presently recommended for the testing of skin sensitization. This is also in agreement with aspects of animal welfare.

Animals↗

PubMed2000

Photosynthesis tests as an alternative to growth tests for hazard assessment of toxicant.

Acute (3- and 6-h) toxic responses toward Cu, linear alkylbenzene sulfonate (LAS), and tributyltin (TBT) of light-saturated and unsaturated photosynthesis were investigated for Rhodomonas salina and Skeletonema costatum obtained from exponentially growing batch cultures and from chemostat cultures limited by either nitrogen or phosphorus. The sensitivity of the photosynthesis tests were compared to standardized growth tests applied to the same species and toxicants. For Cu and S. costatum the photosynthesis test was up to 300 times more sensitive at light saturation than at light limitation. For the remaining photosynthesis tests no dependence on light condition were found. The photosynthesis tests with Cu and S. costatum were up to 10 times as sensitive as the growth test and most sensitive when the algae were obtained from a phosphate-limited chemostate. For the other photosynthesis tests no dependence on the growth condition were found, and the photosynthesis tests were as sensitive as the growth test. Photosynthesis tests offer an alternative to growth tests for hazard assessment of toxicants.

Alkanesulfonic Acids↗

PubMed1995

Neural network prediction of nonstress test results: how often should we perform nonstress tests?

OBJECTIVE: Our purpose was to predict outcomes and optimal intervals for nonstress tests of term gravid women with neural networks. STUDY DESIGN: We studied 100 normal term patients whose 30-minute nonstress tests, performed on 5 consecutive days, were computer analyzed for the following elements: fetal heart rate baseline, variability, signal loss, accelerations (> 15 beats/min), and decelerations. The training set used 65 patients; the testing, 35 patients. Nonstress test data (days 1 to 4) were inputs; day 5 data were training patterns. Networks for each nonstress test element used Brainmaker Macintosh 1.0 (California Scientific Software, Nevada City, Calif.) trained to 0.12 tolerance. Actual fetal heart rate elements and their daily differences were compared with predictions by the networks and multiple regressions. RESULTS: There was little difference between networks using daily or alternate-day inputs for predicting test performance on day 5; networks using test intervals > 2 days could not be trained to tolerance. Long-term fetal heart rate variation was the nonstress test element best predicted. Daily differences networks provided better prediction of all day 5 data than did actual daily values networks or multiple regression formulas. CONCLUSIONS: Baseline long-term fetal heart rate variability seems to be the most predictable fetal heart rate element over time and should merit more consideration in overall fetal testing. Fetal heart rate elements are not easily predicted by any method for intervals longer than 2 days. Using longer test intervals might run a greater risk for unanticipated changes in nonstress test outcomes, even when fetal condition is normal.

Female↗

PubMed1992

Evaluation of the Multi-Test device for immediate hypersensitivity skin testing.

Test-to-test reproducibility, user variability, and the effect of positive reactions on adjacent negative sites were evaluated for the Multi-Test skin testing device. Twenty-five subjects had skin tests with 24 histamine (1 mg/ml), four glycerosaline controls, and four "dry" controls on two testings 7 days apart. To assess reproducibility from large and smaller histamine reactions and/or their effect on adjacent negative controls, 10 of the 25 subjects were retested once with the same testing format, but histamine at 10 mg/ml was substituted. To determine whether large allergen reactions affect adjacent negative controls differently than histamine reactions, 24 additional patients were retested on arms and back with negative controls adjacent to allergens to which they had prior 3+ to 4+ skin test reactions. Conclusions from 2688 skin tests on 49 patients are as follows: large (mean > 10 mm) histamine reactions reproduced better than smaller (mean < 7 mm) responses--coefficients of variation were 12.3 and 21.4 respectively. A 14% user variability occurred when comparing mean wheal sizes from histamine produced by each nurse and 1.2% when comparing their coefficients of variation. Neither small histamine reactions nor large reactions from histamine and allergens affected adjacent negative controls. We conclude that Multi-Test is a highly reliable skin testing technique that provides good reproducibility of results and low user variability.

Adolescent↗

PubMed1990

Exact statistical tests for any carcinogenic effect in animal bioassays. II. Age-adjusted tests.

Statistical methods are discussed for application in animal carcinogenesis bioassays that test a general null hypothesis that response frequencies are independent of the treatment level for all tumor endpoints, sexes, and species considered in the bioassay, conditional on survival. These methods are similar to those proposed earlier by Farrar and Crump (1988, Fundam, Appl. Toxicol. 11, 652-663) which involve test statistics that are functions of p values from multiple standard statistical hypothesis tests, and evaluation of significance using randomization. Refinements include the introduction of an exact incidental tumor test analogous to the asymptotic test of Hoel and Walburg (1972, J. Natl. Cancer Inst. 49, 361-372), which takes into account the possibility that any differences among treatment groups in response rates result from differences in survival that is independent of tumors. Additional consideration is given to selection of test statistics, and a test is proposed that is sensitive specifically to cases where the same tumor endpoints are affected in multiple sexes and species. Applications of the procedures to results of National Toxicology Program (NTP) bioassays concerning decabromodiphenyl oxide and iodinated glycerol illustrate the sensitivity of tests based on different test statistics to distinct alternative hypotheses. When compared with the qualitative conclusions of the NTP regarding the strength of evidence for a carcinogenic effect in the same bioassays, the results presented suggest that the methods can be useful in clarifying otherwise equivocal evidence for carcinogenicity. Various difficulties are discussed relevant to the construction of exact combined fatal and incidental tumor tests analogous to the tests of Peto et al. (1980, IARC Monogr. Suppl. 2).

Age Factors↗