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Test Sensitivity (test + sensitivity)
Selected AbstractsP30 Transparent plastic foils allow a short patch-test application timeCONTACT DERMATITIS, Issue 3 2004Bolli Bjarnason Objective:, To investigate whether application of allergic patch tests with transparent semi-occlusive adhesive plastic foils yields higher test sensitivity than when tapes are used. To study whether such foils compared to tapes allow a shorter application time of tests. Methods:, We applied different doses of budesonide printed on polyester squares and vehicle control squares to budesonide allergic subjects for 4 days. Each subject was tested with a set of tests both with a tape and a foil. We assessed all tests when they had been detached and additionally those applied with foils at earlier time points. All assessments were performed both visually and with a laser Doppler perfusion imaging technique. Results:, Test sensitivity is higher with foil applications than when tapes are used and the perfusion is higher with the foils in many cases. The foils allow detachment of visually positive tests before 48 hours in some subjects, regardless of dose. Conclusions:, Test applications with transparent semi-occlusive adhesive plastic foils is sensitive and should be considered for application of patch tests when a short application time is important as when tests are carried out with occupationally hazardous allergens or when test substances containing allergens are expected to be irritating. [source] Information derived from sensitization test methods: test sensitivity, false positives and false negativesCONTACT DERMATITIS, Issue 1 2007David A. Basketter Predictive toxicology tests for the prospective identification of skin-sensitizing chemicals are well known and have been used for many years. However, of these, only the local lymph node assay (LLNA) has actually undergone formal independent assessment to determine the accuracy of the predictions, particularly with respect to the likelihood of false positives and false negatives. Often, efforts to increase the sensitivity of a test (reducing false negatives) tend to increase the number of false positives. In this short review, these issues are discussed in particular relation to the 3 predictive tests available in regulatory toxicology, the guinea-pig maximization test, the occluded patch test of Buehler and the LLNA. A key perspective is that no predictive test is without limitations; having a good appreciation of these limitations is necessary for making the best use of the information derived from these methods. [source] Identification and classification of skin sensitizers: identifying false positives and false negativesCONTACT DERMATITIS, Issue 5 2006David A. Basketter The first step in regulatory evaluation of substances involves the identification of their intrinsic hazards, including the potential for skin sensitization. This is, quite properly, entirely different from assessment of the risks to human health, which might arise from incorporation of substances in products. EU guidance on regulations concerning the classification of skin sensitizers suggests a range of sources of information be deployed in the hazard identification process. These include chemical structure, predictive animal tests, and various types of human data. Where the information is clear-cut, then uncertainties rarely arise. However, for some materials, discordant information arises, perhaps because the substance is on the borderline of test sensitivity and classification (sensitizing materials of insufficient potency do not classified according to the EU scheme), due to conflicting results in predictive tests or for other reasons. In this study, we review data on a number of substances where a classification decision is complicated by such discordances and seek to use these examples to demonstrate how best to make a weight of evidence decision on whether a substance should, or should not, be classified as a skin sensitizer. [source] The clinical aspects of newborn screening: Importance of newborn screening follow-upDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 4 2006Philip M. James Abstract The aim of newborn screening is to identify presymptomatic healthy infants that will develop significant metabolic or endocrine derangements if left undiagnosed and untreated. The goal of ultimately reducing or eliminating irreversible sequelae is reached by maximizing test sensitivity of the primary newborn screening that measures specific analytes by a number of methodologies. Differentiation of true from false negatives is accomplished by the test specificity. This review discusses disorders for which, in general, there are available therapies and that are detected by routine and expanded newborn screening. Recommendations are presented for evaluation by a primary care physician, with confirmation by a metabolic or endocrinology specialist. Disorders are organized in tabular format by class of pathway or analyte, with attention to typical clinical presentations, confirmatory biochemical and molecular tests, and therapies. There are numerous challenges in clinical follow-up, including diagnosis and appropriate understanding of the consequences of the disorders. The data required to meet these challenges can be acquired only by large scale longitudinal comprehensive studies of outcome in children identified by newborn screening. Only with such data can newborn screening fully serve families. © 2006 Wiley-Liss, Inc. MRDD Research Reviews 2006;12:246,254. [source] Assessment of specimen adequacy reproducibility: An Italian experienceDIAGNOSTIC CYTOPATHOLOGY, Issue 4 2003Gioia Montanari M.D. Abstract Interobserver disagreement on smear adequacy may influence the evaluation of the performance of samplers as well as Pap test sensitivity and follow-up. In 1998, the Italian Group for Cervical Cancer Screening (GISCi) promoted a study on the reproducibility of adequacy criteria using a modified version of the Bethesda system. A set of 200 smears was circulated among six Italian laboratories situated in different parts of the country. For each smear, participants were requested to provide a summary judgment on its adequacy and on the cause(s) of inadequacy, if any. Agreement was measured using kappa-type statistics. The agreement among laboratories was generally good. In comparisons, among five laboratories, kappa values ranged from 0.47 to 0.66. At the consensus meeting on 42 slides, on which at least 2 laboratories dissented from the majority, agreement was reached unanimously for 31 reviewed slides and among 5,6 centers for 11. In this article, some guidance is given in order to attribute to one of the two categories satisfactory/unsatisfactory those smears that have been traditionally considered as candidates for the category of "satisfactory but limited by ," (SBLB). New Italian guidelines on adequacy proposed the GISCi are presented and the recommendation is made to eliminate the SBLB category. Diagn. Cytopathol. 2003;28:224,226. © 2003 Wiley-Liss, Inc. [source] The validity of an Australian modification of the AUDIT questionnaireDRUG AND ALCOHOL REVIEW, Issue 2 2001LOUISA J. DEGENHARDT Abstract The Alcohol Use Disorders Identification Test (AUDIT) has been used widely and is reported to be superior to conventional questionnaires in detection of current hazardous and harmful alcohol use. We assessed the validity of an Australian modification of the AUDIT (the AusAUDIT), which has been employed widely in Australian and New Zealand early intervention programmes. We used a cross-sectional study of 370 subjects from the follow-up phase of a randomized controlled trial of early intervention to reduce hazardous alcohol consumption. Scores on the AusAUDIT were compared against 12-month ICD-10 diagnoses of harmful alcohol use and dependence, as determined by the Composite International Diagnostic Interview, and against self-report of alcohol consumption exceeding Australian National Health and Medical Research Council (NH&MRC) recommended limits. AusAUDIT had good internal consistency and discriminated significantly between persons meeting criteria for ICD-10 alcohol use disorders, and drinkers who did not. At currently recommended cut-off scores, AusAUDIT detected more than 85% of people meeting criteria for ICD-10 alcohol use disorders, or drinking over NH&MRC recommended limits, but its specificity was limited (29% in men, and 58% in women for drinking over NH&MRC limits). No subset of questions performed as well as the full AusAUDIT in detection of drinking problems, but the alcohol consumption items provided a reasonable screen for drinking over NH&MRC limits. We conclude that AusAUDIT is effective in detecting problematic drinking, but positive cases should be confirmed by clinical assessment. The findings illustrate the need for validation of questionnaire modifications, and the difficulty in increasing test sensitivity without reducing specificity. [source] Patent Foramen Ovale: Comparison among Diagnostic Strategies in Cryptogenic Stroke and MigraineECHOCARDIOGRAPHY, Issue 5 2009Concetta Zito M.D. Objective: The aim of this study was to compare transthoracic echocardiography (TTE) and transcranial Doppler ultrasonography (TCD) with transesophageal echocardiography (TEE) in order to define the best clinical approach to patent foramen ovale (PFO) detection. Methods: In total, 72 consecutive patients (33 men) with a mean age of 49 ± 13 years were prospectively enrolled. The TEE indication was cryptogenic stroke (36 patients) or migraine (36 patients, 22 with aura). All patients underwent standard TTE, TCD, and TEE examination. For any study, a contrast test was carried on using an agitated saline solution mixed with urea-linked gelatine (Haemaccel), injected as a rapid bolus via a right antecubital vein. A prolonged Valsalva maneuver was performed to improve test sensitivity. Results: TEE identified a PFO in 65% of the whole population: 56.5% in the migraine cohort and 43.5% in the cryptogenic stroke cohort. TTE was able to detect a PFO in 55% of patients positive at TEE (54% negative predictive value, 100% positive predictive value, 55% sensitivity, and 100% specificity). TCD was able to identify a PFO in 97% of patients positive at TEE (89% negative predictive value, 98% positive predictive value, 94% sensitivity, and 96% specificity). Conclusions: In patients with cryptogenic stroke and migraine, there is a fair concordance (k = 0.89) between TCD and TEE in PFO recognition. Accordingly, TCD should be recommended as a simple, noninvasive, and reliable technique, whereas TEE indication should be restricted to selected patients. TTE is a very specific technique, whose major advantage is the ability to detect a large right-to-left shunt, particularly if associated with an atrial septal aneurysm. [source] Development of a dipstick dye immunoassay for diagnosing hydatidosisJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 6 2003Younes Sbihi Abstract We have developed a kit to diagnose hydatidosis, based on the detection of specific antibodies. This disease, caused by larvae of the cestode Echinococcus granulosus, is a zoonosis commonly found throughout the world. The diagnostic kit discriminates between positive and negative cases in a way that is easily interpreted, i.e., positive cases form a colored band on an inert substrate. The results show test sensitivity to be some 94.87% and specificity 85.71%, which is comparable to those of the ELISA technique. The high sensitivity and specificity of this test affords the great advantage of speed in diagnosing this parasitosis. No other equipment or procedure is required. J. Clin. Lab. Anal. 17:219,222, 2003. © 2003 Wiley-Liss, Inc. [source] Impact of advanced exercise ECG analysis on cost of coronary artery disease managementJOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 4 2010Riccardo Bigi PhD Abstract Background, Conventional analysis of exercise electrocardiogram (EX-ECG) has limited accuracy. This study aims to evaluate the potential impact of improving EX-ECG accuracy on costs of diagnosis and number of misdiagnoses of coronary artery disease (CAD). Methods, A decision-tree model was simulated including sequential application of diagnostic procedures for suspected CAD. The model was structured in two main branches (presence or absence of CAD). A probabilistic sensitivity analysis was then performed for several combinations of improvement in test sensitivity and specificity. Results, A clear trend in cost reduction was observed at improving EX-ECG specificity (about 8,8.5 million dollars, corresponding to a 5.6,7.6% reduction according to the prevalence level). Wrong diagnoses counted for 9,13% of test. Improvements in test parameters lead to reductions in wrong diagnoses, especially when increasing specificity (8.8,12.5%). Conclusions, A proper improvement in EX-ECG sensitivity and specificity would have a relevant impact on the costs of CAD management, while reducing the number of misdiagnoses. [source] Sensitivity of superficial cultures in lower extremity wounds,JOURNAL OF HOSPITAL MEDICINE, Issue 7 2010Chayan Chakraborti MD Abstract BACKGROUND: Superficial wound cultures are routinely used to guide therapy, despite a lack of clear supporting evidence. PURPOSE: To conduct a systematic review of the correlation between superficial wound cultures and the etiology of skin and soft tissue infections. DATA SOURCES: Medline, EMBASE, CINAHL, Scopus. STUDY SELECTION: Articles published between January 1960 and August 2009 involving superficial wound cultures and deeper comparison cultures. DATA EXTRACTION: Two reviewers independently searched for abstracted information pertaining to the microbiology of lower extremity wounds sufficient to calculate the sensitivity and specificity of superficial wound cultures versus comparison cultures. DATA SYNTHESIS: Data pooled using a random-effects meta-analysis model. RESULTS: Of 9032 unique citations, 8 studies met all inclusion criteria. Inter-rater reliability was substantial (Kappa = 0.78). Pooled test sensitivity for superficial wound swabs was 49% (95% confidence interval [CI], 37-61%], and specificity was 62% (95% CI, 51-74%). The pooled positive and negative likelihood ratios (LRs) were 1.1 (95% CI, 0.71-1.5) and 0.67 (95% CI, 0.52-0.82). The median number of isolates for surface cultures (2.7, interquartile range [IQR] 1.8-3.2) was not significantly different than that for comparison cultures, (2.2, IQR 1.7-2.9) (P = 0.75). CONCLUSION: Few studies show a strong relationship between superficial wound swabs and deep tissue cultures, and the current data demonstrate poor overall sensitivity and specificity. The positive and negative LRs were found to provide minimal utility in influencing pretest probabilities. Results of this analysis show that wound cultures should not be used in lieu of local antibiograms to guide initial antibiotic therapies. Journal of Hospital Medicine 2010;5:415,420. © 2010 Society of Hospital Medicine. [source] Acute retinal necrosis six years after herpes simplex encephalitis: An elusive immune deficit suggested by insufficient test sensitivityJOURNAL OF MEDICAL VIROLOGY, Issue 2 2004W. Preiser Abstract A patient presented with acute retinal necrosis of the left eye. Demonstration of herpes simplex virus (HSV) DNA in the aqueous humour confirmed the diagnosis. Negative results of HSV type-specific antibody tests based on gG antigens suggested a primary HSV infection. However, the patient had a past history of laboratory-confirmed herpes simplex encephalitis 6 years ago. Using antibody tests based on whole viral lysate antigens, he was seropositive from the onset, and immunoblot testing confirmed a lack of anti-gG reactivity. To be able to assess whether this might be related to the apparent inability of his immune system to suppress clinically symptomatic HSV infection, serial samples were tested by an HSV neutralisation test and a whole-blood flow cytometric assay to determine the frequency of HSV-specific CD4 lymphocytes. However, this did not yield evidence of obvious immunodeficiency; the patient reacted similarly to known positive controls by both assays. Although type-specific HSV serological tests based on gG are generally more specific than those based on whole viral lysate antigens, they have a somewhat lower sensitivity, as a certain percentage of HSV-infected individuals do not develop antibodies against gG, and others may suffer a secondary loss of anti-gG reactivity. Thus there is a risk of missing individual infected patients. Unless this potential problem is recognised, serious consequences might possibly result. We therefore urge virologists and clinicians to exercise great care if highly specific antibody assays based on recombinant proteins are employed. J. Med. Virol. 73:250,255, 2004. © 2004 Wiley-Liss, Inc. [source] Gloss control in rigid PVC,Part I. Techniques for gloss assessment of rigid PVC profilesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2000Elvira Rabinovitch This paper describes various techniques for assessing the gloss of PVC extrudates. It discusses the effect of the incident light angle on measured gloss values and the test sensitivity. It also describes the relationship between surface gloss and extrudate roughness, as analyzed by scanning electron microscopy and optical microscopy. Finally, this paper provides recommendations on the most suitable methods for assessing the gloss of PVC extrudates. [source] The Effect of Time-Series and Cross-Sectional Heterogeneity on Panel Unit Root Test PowerTHE JOURNAL OF FINANCIAL RESEARCH, Issue 3 2002John M. Geppert Abstract Panel unit root tests represent a significant advancement in addressing the low power of unit root tests by exploiting cross-sectional and time-series information. In this article we employ Monte Carlo techniques to quantify the power improvements due to cross-sectional information and assess test sensitivity to heterogeneous data. Pooling the data alleviates negative effects of slowly adjusting equilibrium relations as well as persistence in the forcing variable. However, if the panel contains a mixture of unit root and stationary series, the power of the test decreases substantially and the interpretation of the results becomes tenuous. [source] Sensitivity of moist convection to environmental humidityTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 604 2004S. H. Derbyshire Abstract As part of the EUROCS (EUROpean Cloud Systems study) project, cloud-resolving model (CRM) simulations and parallel single-column model (SCM) tests of the sensitivity of moist atmospheric convection to midtropospheric humidity are presented. This sensitivity is broadly supported by observations and some previous model studies, but is still poorly quantified. Mixing between clouds and environment is a key mechanism, central to many of the fundamental differences between convection schemes. Here, we define an idealized quasi-steady ,testbed', in which the large-scale environment is assumed to adjust the local mean profiles on a timescale of one hour. We then test sensitivity to the target profiles at heights above 2 km. Two independent CRMs agree reasonably well in their response to the different background profiles and both show strong deep precipitating convection in the more moist cases, but only shallow convection in the driest case. The CRM results also appear to be numerically robust. All the SCMs, most of which are one-dimensional versions of global climate models (GCMs), show sensitivity to humidity but differ in various ways from the CRMs. Some of the SCMs are improved in the light of these comparisons, with GCM improvements documented elsewhere. © Crown copyright, 2004. [source] Thyromental distance measurement , fingers don't ruleANAESTHESIA, Issue 8 2009P. A. Baker Summary Thyromental distance (TMD) measurement is commonly used to predict difficult intubation. We surveyed anaesthetists to determine how this test was being performed. Comparative accuracy of ruler measurement and other forms of measurement were also assessed in a meta-analysis of published literature. Of respondents, 72% used fingers for TMD measurement and also considered three finger widths the minimum acceptable TMD. In terms of distance, the minimum acceptable TMD was felt to be 6.5 cm by 55% of respondents. However, the actual width of three fingers was (range) 4.6,7.0 cm (mean 5.9 cm), with significant differences between genders and between proximal and distal interphalangeal joints. The meta-analysis showed ruler measurement increased test sensitivity (48% (95% CI 43,53) vs 16% (95% CI 14,19) without a ruler), when predicting difficult intubation. [source] Validation of a bedside activated clotting time test (Hemochron® Jr II Signature) with low dose heparin therapyANAESTHESIA, Issue 4 2009L. Racioppi Summary The purpose of this study was to validate a device designed to measure activated clotting time in low-range heparin plasma concentrations (ACT-LR) prospectively during the post-operative period of vascular surgery. Measurement of ACT-LR and activated partial thromboplastin time (APTT) were performed before heparinisation (T0) and at the end of surgery (T1). ACT-LR(T1) and ,ACT-LR (defined as ACT-LR(T1) , ACT-LR(T0)) were evaluated as diagnostic tests for excessive anticoagulation, defined by APTT more than twice the laboratory's normal, by Bland-Altman method and receiver operating characteristic (ROC) curves. In 103 patients, mean (SD) ACT-LR was 137 (33) s at T0 and 176 (39) s at T1. Bland-Altman graph did not show a good agreement between APTT and ACT-LR. Areas under ROC curves were 0.82 (95% CI: 0.75,0.89) and 0.87 (95% CI: 0.80,0.93) for ACT-LR(T1) and ,ACT-LR, respectively. Using a threshold of 32 s for ,ACT-LR, test sensitivity was 87% (95% CI: 81,93%), specificity was 85% (95% CI: 78,92%), positive predictive value was 90% (95% CI: 84,96%) and negative predictive value was 81% (95% CI: 73,86%). While ,ACT-LR may have some potential in evaluating excessive anticoagulation in vascular surgery, the poor correlation between ACT-LR and APTT does not support its routine use. [source] Potential Impact of Adjusting the Threshold of the Quantitative D-dimer Based on Pretest Probability of Acute Pulmonary EmbolismACADEMIC EMERGENCY MEDICINE, Issue 4 2009Christopher Kabrhel MD Abstract Objectives:, The utility of D-dimer testing for suspected pulmonary embolism (PE) can be limited by test specificity. The authors tested if the threshold of the quantitative D-dimer can be varied according to pretest probability (PTP) of PE to increase specificity while maintaining a negative predictive value (NPV) of >99%. Methods:, This was a prospective, observational multicenter study of emergency department (ED) patients in the United States. Eligible patients had a diagnostic study ordered to evaluate possible PE. PTP was determined by the clinician's unstructured estimate and the Wells score. Five different D-dimer assays were used. D-dimer test performance was measured using 1) standard thresholds and 2) variable threshold values: twice (for low PTP patients), equal (intermediate PTP patients), or half (high PTP patients) of standard threshold. Venous thromboembolism (VTE) within 45 days required positive imaging plus decision to treat. Results:, The authors enrolled 7,940 patients tested for PE, and clinicians ordered a quantitative D-dimer for 4,357 (55%) patients who had PTPs distributed as follows: low (74%), moderate (21%), or high (4%). At standard cutoffs, across all PTP strata, quantitative D-dimer testing had a test sensitivity of 94% (95% confidence interval [CI] = 91% to 97%), specificity of 58% (95% CI = 56% to 60%), and NPV of 99.5% (95% CI = 99.1% to 99.7%). If variable cutoffs had been used the overall sensitivity would have been 88% (95% CI = 83% to 92%), specificity 75% (95% CI = 74% to 76%), and NPV 99.1% (95% CI = 98.7% to 99.4%). Conclusions:, This large multicenter observational sample demonstrates that emergency medicine clinicians currently order a D-dimer in the majority of patients tested for PE, including a large proportion with intermediate PTP and high PTP. Varying the D-dimer's cutoff according to PTP can increase specificity with no measurable decrease in NPV. [source] Renal concentrating capacity as a marker for glomerular filtration rateACTA PAEDIATRICA, Issue 1 2008Víctor M García Nieto Aim: We have studied 160 children with a variety of renal diseases, 14 of them with chronic renal failure (CRF), to evaluate maximum urinary osmolality as a predictor of glomerular filtration rate (GFR) testing the hypothesis that a normal GFR is necessary to have a normal urinary concentrating capacity. Methods: All patients had a serum creatinine measured. GFR was calculated according to the Schwartz formula. All patients underwent desmopressin (DDAVP) test to evaluate renal concentrating capacity. Results: Patients with CRF were unable to concentrate the urine beyond 486 mosm/kg whereas all patients with a normal concentrating capacity (urine osmolality > 835 mosm/kg) had a normal GFR. Desmopressin test sensitivity to detect CRF was 100% and specificity 70.5%. A significant negative correlation was found between urinary osmolality after DDAVP administration and serum creatinine levels and between urinary volume corrected by 100 mL of GFR (V/GFR) and urinary osmolality. Conclusion: In our series, a normal concentrating capacity was always associated with a normal GFR while all patients with decreased GFR had a concentrating capacity defect. Thus, in the evaluation of infants and children with renal disease, the finding of a normal urinary concentrating capacity will suggest and intact glomerular and tubular function. [source] The use of the QNST,II as a measure for the identification of children with perceptual-motor deficitsOCCUPATIONAL THERAPY INTERNATIONAL, Issue 3 2002Shula Parush PhD Abstract This study aimed to examine the ability of the Quick Neurological Screening Test,II (QNST,II) (Mutti et al., 1998) to discriminate between children with and without perceptual-motor deficits and to further clarify its psychometric characteristics. Ninety-four children aged six to seven years were tested on the QNST-II. Out of this pool of subjects, 63 children had perceptual-motor deficits and 31 were typical controls. The children with perceptual-motor deficits scored significantly lower than the control children on the total score and on each of the subtest's scores of the QNST,II. Inter-rater reliability indicated a high degree of correlation between both evaluators' total scores of the QNST,II. In terms of the test's sensitivity and specificity, QNST,II scores correctly classified 97% of the children with perceptual-motor deficits and 84% of the children from the control group. The findings of this study support the capability of the QNST,II to discriminate between children with perceptual-motor deficits and typical children; thereby suggesting its usefulness as a screening measure to identify children at risk for difficulties in school performance. Copyright © 2002 Whurr Publishers Ltd. [source] Skin testing for immediate hypersensitivity to betalactams: comparison between two commercial kitsALLERGY, Issue 8 2006J. L. Rodríguez-Bada Introduction:, Skin testing with major and minor determinants of benzylpenicillin is the recommended standard practice to evaluate subjects with immediate hypersensitivity to betalactams. The withdrawal of these products from the market has set us back to the early days, before the introduction of reagents for in vivo testing. Objectives:, To compare a recently released kit of benzylpenicillin conjugated to poly- l -lysine (PPL) and minor determinants mixture (MDM) with the previously existing kit in a positive control group of subjects sensitized to major and/or minor determinants of benzylpenicillin. Methods:, Skin tests with both kits were made in a group of positive subjects previously diagnosed with immediate hypersensitivity to penicillins and with positive results to PPL and/or MDM and in a negative control group. Radioallergosorbent test (RAST) inhibition assays with a pool of sera and individual samples were carried out to compare the inhibition capacity of PPL and MDM of both kits. Results:, Of 22 cases selected from our historical group, 14 were positive: eight to PPL, three to MDM and three to both. These results were equivalent for both kits. RAST inhibition studies showed similar potencies in the inhibition of PPL and MDM. Conclusions:, Both tests show similar results in terms of RAST inhibition assays and skin tests sensitivity and specificity in the groups selected. The new assay can be used for the same purpose and indications as the previous test. [source] |