Negative predictive value of urine dipstick testing.
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England↗
SEARCH · PubMed Health
Results for “Predictive Value of Tests”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
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A computerized program of skin test evaluation and its predictive value in immunotherapy.
The present study describes a computerized methodology for the assessment of specific skin testing which is both sensitive and reproducible. We evaluated the predictive value of this technique in identifying patients at great risk for developing undesirable reactions during hyposensitization. In 11 of 93 patients we were able to detect an unusual dermal response in the patients who developed either generalized or local generalized adverse reactions.
Adolescent↗
Usefulness of ambulatory silent myocardial ischemia added to the prognostic value of exercise test parameters in predicting risk of cardiac death in patients with stable angina pectoris and exercise-induced myocardial ischemia.
The prognostic significance of ambulatory silent ischemia detected by Holter monitoring during daily life was prospectively evaluated and compared with several exercise test parameters in 86 patients with stable angina and positive exercise tests. Forty-seven patients (group 1) had no evidence of ischemia and 39 (group 2) had 1 or more episodes of silent ischemia during the monitoring period. During mean follow-up of 24 +/- 8 months there were only 2 cardiac deaths (nonsudden) in group 1 (4% mortality) compared with 9 (3 sudden and 6 nonsudden) in group 2 (23% mortality). Kaplan-Meier actuarial analysis revealed worse survival (p less than 0.008) for patients in group 2. The Cox regression analysis of clinical variables, electrocardiographic and exercise parameters, angiographic data and Holter monitoring results revealed silent ischemia during daily life as the most powerful predictor of cardiac mortality (p = 0.003). These results demonstrate that in patients with chronic stable angina and abnormal exercise tests, ambulatory ischemia detected by Holter monitoring provides significant additional prognostic information to that derived from evaluation of exercise test parameters alone.
Actuarial Analysis↗
Glaucoma screening by optometrists: positive predictive value of visual field testing.
PURPOSE: Visual field testing is increasingly being performed by optometrists in order to improve glaucoma detection. The aim of this study was to assess the positive predictive value (PPV) of visual field testing as currently practised by optometrists. METHODS: A retrospective study was performed of referrals for suspected glaucoma to an ophthalmology department during a 3 month period. The PPV for glaucoma was determined according to the reason for referral. RESULTS: There were 86 referrals for suspected glaucoma. Isolated field loss accounted for 12% of these referrals but no cases of glaucoma detection. These subjects were either false positive referrals or had field defects of nonglaucomatous aetiology (tilted optic disc and porencephalic cyst). The PPV for glaucoma among referrals with isolated field loss was significantly less than that among referrals with field loss in association with corroborative abnormalities (0 vs. 60%, p = 0.005). No such difference was found for referrals with raised intraocular pressure (43% vs. 57%, p = 0.38) or suspicious discs (25% vs. 53%, p = 0.60). CONCLUSIONS: Visual field testing is currently leading to unnecessary referrals to the hospital eye service with no detectable improvement in the accuracy of glaucoma suspect referrals. It is important that optometrists perform visual field testing in accordance with validated screening methodology.
Adult↗
Estimating the predictive value of a diagnostic test. How to prevent misleading or confusing results.
The diagnostic process consists of a series of steps in which the estimated probability of particular disease is increased or decreased until either treatment can be instituted or the diagnosis excluded. The history and physical exam play an important role. If a therapeutic decision cannot confidently be made on clinical grounds alone, a diagnostic test may confirm or exclude a diagnosis or clearly indicate the need for further testing. An inappropriately chosen test or misinterpreted test result, however, may mislead the clinician and possibly harm the patient or simply be wasteful. Estimating the predictive values of a diagnostic test will help to avoid these pitfalls. This article shows the clinician a simplified way to do this.
Child↗
The prevalence and predictive value of abnormal preoperative laboratory tests in elderly surgical patients.
UNLABELLED: Because data to determine which preoperative laboratory tests are important in elderly surgical patients are limited, we performed a prospective cohort study to evaluate the prevalence and predictive value of abnormal preoperative laboratory tests in consecutive patients > or =70 yr old who were undergoing noncardiac surgery. Patients presenting for surgery requiring only local anesthesia or monitored anesthesia care were excluded. Preoperative risk factors and laboratory test results were measured and evaluated for their association with the occurrence of predefined in-hospital postoperative adverse outcomes. In 544 patients, the prevalence of preoperative electrolytes and platelet count abnormalities (<115 x10(9)/L) was small (0.5%-5%), and abnormal creatinine (>1.5 mg/dL), hemoglobin (<10 g/dL), and glucose (>200 mg/dL) values were 12%, 10%, and 7%, respectively. Univariate predictors for adverse outcome of abnormal sodium and creatinine were not as predictive as ASA classification and surgical risk. By multivariate logistic regression, only ASA classification (>II) (odds ratio [OR], 2.55; 95% confidence interval [CI], 1.56-4.19; P < 0.001) and surgical risk (OR, 3.48; 95% CI, 2.31-5.23; P < 0.001) were significant independent predictors of postoperative adverse outcomes. The prevalence of abnormal preoperative electrolyte values and thrombocytopenia was small and had low predictive values. Although more prevalent, abnormal hemoglobin, creatinine, and glucose values were also not predictive of postoperative adverse outcomes. Routine preoperative testing for hemoglobin, creatinine, glucose, and electrolytes on the basis of age alone may not be indicated in geriatric patients. Rather, selective laboratory testing, as indicated by history and physical examination, which will determine patient's comorbidities and surgical risk, seems to be indicated. IMPLICATIONS: The prevalence of abnormal preoperative electrolyte values and thrombocytopenia was small and had low predictive values. Although more prevalent, abnormal hemoglobin, creatinine, and glucose values were also not predictive of postoperative adverse outcomes. Routine preoperative testing for hemoglobin, creatinine, glucose, and electrolytes on the basis of age alone may not be indicated in geriatric patients. Rather, selective laboratory testing, as indicated by history and physical examination, which will determine patient's comorbidities and surgical risk, seems to be indicated.
Aged↗
Role of pathology indices in the management of severe lupus glomerulonephritis. Lupus Nephritis Collaborative Study Group.
The principal value of the renal biopsy in patients with SLE is as a therapeutic guide. Although semiquantitative indices of nephron loss (chronicity = CI) and acute potentially reversible inflammation (activity = AI) are reported by some to have separate values from traditional classifications of glomerular pathology as predictors of outcome and therapeutic guides, this point remains controversial. We have tested the predictive value of the AI and CI in a large group of patients with severe lupus glomerulonephritis (SLE GN) and a mean follow-up of 281 weeks +/- 116 (mean +/- SD). A total of 86 patients entered into the study of plasmapheresis in severe SLE GN by the Lupus Nephritis Collaborative Study Group, and long-term follow-up was available in 83. The predictive value of the AI and the CI was described over the entire range of cut-off points by the method of receiver operator characteristics (ROC). ROC analysis demonstrated that there was no level of either AI or CI that predicted the outcome of death or renal failure with sufficient sensitivity and specificity to be useful in the individual patient. The CI signifies renal damage and nephron loss, whereas the AI describes potentially reversible pathology. Neither the CI nor the AI taken by itself predicts individual outcomes of renal failure or death in patients with aggressively treated SLE GN. Since the indices fail to identify the patient whose disease will progress to renal failure, they are both insufficient as therapeutic guides and add little to the management of the patient with severe SLE GN.
Adult↗
Regression-based developmental models exemplified for Wisconsin Card Sorting Test parameters: statistics and software for individual predictions.
The prediction of an individual's score is relevant in clinical research and requires normative data and a statistical rationale. In the case of developmental research the latter is typically a set of descriptive statistics (e.g., standard scores) for a set of age groups. Here we illustrate a multiple regression approach with a set of 345 Wisconsin Card Sorting Test (WCST) data obtained from subjects aged 6 to 26 years. We modeled linear and curvilinear age effects for each of the 11 WCST variables and, based on this, determined confidence limits for the expected value (mean) and the prediction of individual scores. In these multiple regression models, which accounted for 2% to 26% of the variance, curvilinear age effects clearly dominated linear ones, suggesting the features under scrutiny to be negatively accelerated functions of age. Finally, we developed a statistics program that can be used to apply multiple regression models for individual predictions that are based on normative data with up to 7 predictor variables. We discuss the conditions of applicability of the approach, compare it with the conventional standard score approach, discuss its cognitive-developmental implications, and outline the applicability in applied research and practising.
Adolescent↗
Predicting motor outcome at preschool age for infants tested at 7, 30, 60, and 90 days after term age using the Test of Infant Motor Performance.
BACKGROUND AND PURPOSE: Accurate and diagnostic measures are central to early identification and intervention with infants who are at risk for developmental delays or disabilities. The purpose of this study was to examine (1) the ability of infants' Test of Infant Motor Performance (TIMP) scores at 7, 30, 60 and 90 days after term age to predict motor development at preschool age and (2) the contribution of the home environment and medical risk to the prediction. SUBJECTS AND METHODS: Sixty-one children from an original cohort of 90 infants who were assessed weekly with the TIMP, between 34 weeks gestational age and 4 months after term age, participated in this follow-up study. The Peabody Developmental Motor Scales, 2nd edition (PDMS-2), were administered to the children at the mean age of 57 months (SD=4.8 months). The quality and quantity of the home environment also were assessed at this age using the Early Childhood Home Observation for Measurement of the Environment (EC-HOME). Pearson product moment correlation coefficients, multiple regression, sensitivity and specificity, and positive and negative predictive values were used to assess the relationship among the TIMP, HOME, medical risk, and PDMS-2 scores. RESULTS: The correlation coefficients between the TIMP and PDMS-2 scores were statistically significant for all ages except at 7 days. The highest correlation coefficient was at 90 days (r=.69, P=.001). The TIMP scores at 30, 60, and 90 days after term; medical risk scores; and EC-HOME scores explained 24%, 23%, and 52% of the variance in the PDMS-2 scores, respectively. The TIMP score at 90 days after term was the most significant contributor to the prediction. The TIMP cutoff score of -0.5 standard deviation below the mean correctly classified 80%, 79%, and 87% of the children using a cutoff score of -2 standard deviations on the PDMS-2 at 30, 60, and 90 days, respectively. DISCUSSION AND CONCLUSION: The results compare favorably with those of developmental tests administered to infants at 6 months of age or older. These findings underscore the need for age-specific test values and developmental surveillance of infants before making referrals.
Child Behavior↗
Predictive value of the routine testing ECG for serious ventricular arrhythmias.
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Aerospace Medicine↗
An evaluation of microcult g.c. in venereal disease clinics.
Microcult G.C. is a kit for cultivation and identification of Neisseria gonorrhoeae. ue of this kit was compared with the cultivation and identification methods of the Neisseria Department, Statens Seruminstitut, Copenhagen (WHO collaborating center for reference and research in gonococci). The investigation included 203 men and 80 women who appeared for examination at our veneral disease clinics. For examination of urethral specimens from men the predictive value of positive tests was found to be 93% and the predictive value of negative tests was 94%. For specimens from the urethra and cervix of women, the predictive value of positive tests was 95% and the predictive value of negative tests was 90%. The reliability of these results makes Microocult G.C. a valuable supplement to microscopy in venereal disease clinics with a relative high prevalence of gonorrhoea. The predictive value of positive tests from the anal canal was 21% and from the tonsils 3%; in these locations the test is not suitable for diagnostic purposes.
Anus Diseases↗
Population-based prediction equations for neurobehavioral tests.
Quantitative assessment of neurobehavioral function appraises brain injury from inhaled chemicals. Contemporary predicted values for tests useful in epidemiological studies have been developed with step-wise linear regression. In instances in which age and education do not match those of control groups, these equations assist in the interpretation of results of examinations of individual subjects and pilot studies. In this study, investigators considered brain function tests to be analogous in concept to pulmonary function tests. The authors used the tests to assess 293 adults in three unexposed groups from different areas of the United States. The subjects, who were contacted at random from voter registration rolls, were compensated for their time. The tests included balance, reaction time, strength, hearing, visual performance and cognitive recall, and perceptual motor and memory functions. Regression equations modeled the performance of each test and the influences of demographic factors. The investigators retained all influential factors in the equations. Age was a significant predictor for most tests. Education attainment was not a factor in any of the physiological measures, but it was a determinant in many psychological tests. Prediction equations assist investigators in the quantitative testing of chemically exposed individuals and other brain-injured individuals. The investigators verified the equations against other groups, including additional unexposed populations.
Adolescent↗
Value of otoneurological tests in the staging of multiple sclerosis.
We looked for correlations between otoneurological findings and neurological signs in multiple sclerosis (MS). 41 patients were tested for: spontaneous and caloric nystagmus, horizontal pursuit eye tracking, full-field optokinetic nystagmus and eye movements. The findings were compared with the course of the disease (progressive or remitting), age at onset of MS and disability, in order to test the predictive value of this type of test. The correlation between otoneurological abnormalities and lesion site is very high for brainstem lesions. Subclinical brainstem lesions were detected in 66% of patients with optic neuritis only and in 42% of those with spinal cord involvement only. Eye movement disorders are more frequent (p less than 0.1) in disease of long duration. The vestibular examination was altered in 100% of patients with clinically definite and probable MS, in 91% of those with possible and in 80% of those with suspected MS. No specific otoneurological pattern was identified. No significant correlation with age at onset or with disability was found.
Adult↗
Geographic variation of the predictive values of genomic mutations associated with streptomycin resistance in Mycobacterium tuberculosis.
Specific mutations associated with resistance to streptomycin (SM) in Mycobacterium tuberculosis suggest themselves for its rapid prediction. However, as with any diagnostic test, their predictive values are dependent on their prevalences. In this report, SM resistance associated mutations in the rrs and rpsL genes of 25 SM resistant isolates from Germany and 25 SM resistant isolates from Sierra Leone were characterized and compared. Mutations in the rrs gene were infrequent in isolates from both localities (20% and 12%, respectively) and thus of limited predictive values. In contrast, rpsL mutations were found in 48% of the German isolates but only in 24% of the isolates from Sierra Leone. It is concluded that the predictive values of mutations in this gene may vary significantly with the origin of the samples under investigation.
Antibiotics, Antitubercular↗
Prediction of risk for human developmental toxicity: how important are animal studies for hazard identification?
To determine how developmental toxicity studies in animals can be used in human risk assessment, a data base was assembled from the literature. It included probable, suspected, unknown, and probably negative teratogenic or embryotoxic drugs and chemical compounds. For each of 175 substances, we recorded the results of any developmental toxicity testing in up to 14 animal species and any reports of mutagenicity or carcinogenicity. Logistic regression and discriminant analysis were used to predict a compound's effect in humans. A measure of the number of positive animal studies and bacterial mutagenicity were important predictors in both models, as were the specific results in hamsters and subhuman primates. The fact that a compound had been tested at all in subhuman primates was more important in predicting human risk than was the result itself. The methods used correctly classified the study compounds 63-91% of the time, depending upon how the suspicious and unknown compounds were treated. The models had a sensitivity of 62-75%, a positive predictive value of 75-100%, and a negative predictive value of 64-91%. These findings imply that studies in laboratory animals carry weight in predicting human developmental toxicity. The more animal species in which a compound is positive, the more likely it is to have a human effect, albeit not the same effect as in the animals. Clinicians should not ignore developmental toxicity tests in animals "because laboratory rats are not like humans."
Abnormalities, Drug-Induced↗
In-house assessment of a modified in vitro cytotoxicity assay for higher throughput estimation of acute toxicity.
The main objective of this study was to assess an in-house 3T3 NRU cytotoxicity assay for compatibility with a prediction model for acute rodent oral toxicity endorsed by an NIEHS-ICCVAM workshop. The aim is to use the NRU assay as one test component of HTS strategies for both acute oral toxicity and acute skin irritation, enabling the rejection of the most toxic materials and prioritisation of other materials for further testing. Groups of model cytotoxins and irritants were tested using the NRU assay and their EC50 values obtained from dose-response curves. These values were compared with those estimated from a limited (three)-dose protocol, deemed more suitable for HTS. A good correlation was observed between the EC50 values from both dose-response curves (R2=0.94). The relationships between EC50 values and acute rodent oral toxicity were compared by application of the prediction model to the model cytotoxins. The results from both full and limited dose-responses fitted within the acceptance limits of the prediction model, with regression lines similar to that of the model. Results indicated that the performance of the currently used 3T3 NRU cytotoxicity assay was similar to that of the assays used to generate the data employed in developing the prediction model. This prediction model can be applied with both the standard and HT assays to estimate acute rodent oral toxicity.
Administration, Oral↗
Readmission for newborn jaundice: the value of the Coombs' test in predicting the need for phototherapy.
Current practice at our hospital is to perform a direct antiglobulin test (DAT) on cord blood samples of all infants born to blood type O or Rh-negative mothers. Measurement of serum total bilirubin (STB) level and follow-up after discharge are at the discretion of the individual physician. The purposes of the present study were, first, to determine the clinical utility of performing a routine DAT and, second, to define the clinical characteristics of infants readmitted to the hospital for phototherapy. The study was done over a 1-year period extending from January 1 to December 31, 2000. A retrospective review of the DAT results of all infants born to type O or Rh-negative mothers was conducted. The 2 groups of infants included those who had a positive cord blood DAT and were treated with phototherapy and those who needed readmission to the hospital for phototherapy. We found that routine DAT testing of cord blood from term nonjaundiced infants born to O positive mothers is not necessary. Infants with 2 or more risk factors for jaundice irrespective of the results of the DAT are at an increased risk for needing readmission for phototherapy.
ABO Blood-Group System↗
Plasma von Willebrand factor antigen concentration as a predictor of von Willebrand's disease status in German Wirehaired Pointers.
OBJECTIVE: To evaluate the use of plasma von Willebrand's factor (vWF) concentration as a screening test for inherited von Willebrand's disease (vWD) in German Wirehaired Pointers (GWHP). DESIGN: Prospective study. SAMPLE POPULATION: Plasma samples from 467 GWHP. PROCEDURE: Plasma vWF concentrations were measured as vWF antigen (vWF:Ag), using ELISA, and test values were used to estimate prevalence of vWD in GWHP and predict parental vWD status. Test results of progeny from matings of carrier and noncarrier parents were then compared with the predicted outcome of such matings. RESULTS: 376 (81%) GWHP were classified as vWD noncarriers, 58 (12%) as carriers, and 5 (1%) as affected with vWD. An additional 28 (6%) GWHP could not be classified on the basis of plasma vWF:Ag concentration. The observed outcome of tests of 213 pups was not significantly different from that predicted on the basis of parental vWF:Ag concentration. The predictive value of a positive test result (vWF: Ag% < 50) for identifying vWD carriers was 0.89. CLINICAL IMPLICATIONS: Plasma vWF:Ag concentration was an effective predictor of genetic status for the vWD trait, and for the outcome of matings between carriers and noncarriers of vWD in this study of GWHP.
Animals↗