In vitro and skin testing for allergy: comparable clinical utility and costs.
Controversy exists concerning the appropriate use of skin testing and in vitro testing for the diagnosis of allergy, particularly inhalant allergy. Earlier comparisons of skin testing and in vitro testing concluded that skin testing had superior accuracy at lower expense. In light of new developments with in vitro allergy testing, however, this issue should be reconsidered. A review of the recent scientific literature indicates that in vitro and skin testing are highly correlated. However, without the existence of an independent gold standard for inhalant allergy, it is not possible to determine which test is more accurate. The accuracy of either test can be compromised if conducted using different protocols or having insufficient quality control. Given their respective trajectories for technological advancement, quantification, and quality control, in vitro testing may offer the more standardized approach. Although the cost per test of in vitro testing remains greater than that of skin testing, the per-patient costs of the two modalities appear to be comparable, given the greater number of allergens typically used in skin testing. In summary, both skin testing and in vitro testing are acceptable as frontline diagnostic tools. (+info)
Establishment of predictive variables associated with testicular sperm retrieval in men with non-obstructive azoospermia.
Although testicular biopsy for sperm extraction is a procedure with a potential for complications, sperm retrieval is successful in 30-70% of patients with non-obstructive azoospermia. In order to predict the probability of retrieving at least one testicular spermatozoon we conducted a prospective study of a set of variables in 40 patients with non-obstructive azoospermia. Using the receiver operating characteristic curves, we determined the probability estimates of testicular volume, plasma follicle stimulating hormone (FSH) concentration, Johnsen score and visualization of testicular spermatids in discriminating between patients with successful and failed testicular sperm extraction. Visualization of testicular spermatids provided the best estimate of success of testicular sperm extraction. Of the factors studied using logistic-regression analysis (age, maternal and paternal age at birth, body mass index, luteinizing hormone, testosterone, FSH, testicular volume, the presence of testicular spermatids and Johnsen score), only the presence of spermatids and Johnsen score were independent variables able to predict the success of testicular sperm extraction. The visualization of the presence of spermatids gave a correct prediction of 77% and Johnsen score of 71%. The diagnostic model derived from these independent predictors when validated in 40 patients using the Jackknife technique gave a correct overall prediction of 87%. The probability of successful testicular sperm extraction in patients with non-obstructive azoospermia could be objectively predicted on the basis of simple histopathological criteria represented by the visualization of testicular spermatids and Johnsen score. (+info)
Induced sputum in adolescents with severe stable asthma. Safety and the relationship of cell counts and eosinophil cationic protein to clinical severity.
This study examined the safety of sputum induction and the relation between sputum cell counts and clinical parameters in adolescents with severe persistent asthma. Within 5 days, induced sputum and reversibility in forced expiratory volume in one second (FEV1), quality of life, provocative concentration causing a 20% fall in FEV1 (PC20) of adenosine monophosphate and histamine, exercise-induced bronchoconstriction, overall asthma severity index, and blood eosinophils were collected in 20 atopic adolescents with moderate-to-severe persistent asthma (12-18 yrs of age, FEV1 65-110% of predicted, on 500-2,000 microg inhaled steroids daily). FEV1 was reversible by 13.3-2.3% pred. After sputum induction, FEV1 was still increased by 9.0+/-2.6% pred as compared to the pre-salbutamol baseline. Sputum contained, median (range): 12.4 (0.4-59.5)% squamous cells, 47.3 (6.8-84.0)% macrophages, 39.0 (4.6-84.8)% neutrophils, 4.8 (1.0-12.4)% lymphocytes, 0.4 (0-10.8)% eosinophils and 3.6 (0-23.4)% bronchial epithelial cells. Sputum eosinophils showed a trend towards a significant association with the overall asthma severity index (r=0.46, p=0.06) and correlated inversely with baseline FEV1 (r=-0.51, p=0.03). In conclusion, sputum can be induced safely in adolescents with moderate-to-severe persistent asthma, if pretreated with beta2-agonists. Despite relatively low sputum eosinophil counts in these patients on inhaled steroids, the association of eosinophil numbers with baseline forced expiratory volume in one second and asthma severity index favours a role of induced sputum in monitoring adolescents with severe asthma. (+info)
The basic clinical diagnostic framework synergized.
OBJECTIVE: To develop a diagnostic framework that would help defining clinical problems by the expanded understanding with traditional Chinese medicine (C Med) and western medicine (W Med). METHODS: The basic attributes of diagnosis and the use of diagnostic techniques of W Med and C Med are reviewed. Some of the various diagnostic labels and their meanings are also preliminarily reviewed. A consolidatory approach is made to synergize the usefulness of the two disciplines based on the principles of the two schools. RESULTS: A synergized basic diagnostic framework is developed. The disease (the disease diagnosis, [symbol: see text]), the state of the inner core (the core diagnosis, [symbol: see text]) should be defined. The term "systemic clues" is used to describe the symptom complex and conglomerate evidence describing the transient or sustained reaction of the inner core to environment. This is an analytical summary of its pathophysiological changes in reaction to the environmental insults. CONCLUSIONS: The application and use of the framework are discussed and propositions are made. The synergized diagnostic platform represents a starting effort to form a unified basis to exchange clinical diagnosis between W Med and C Med. Such framework may facilitate looking for new treatment modalities and results can be compared across different centres. (+info)
Selecting diagnostic tests for ruling out or ruling in disease: the use of the Kullback-Leibler distance.
BACKGROUND: To select a proper diagnostic test, it is recommended that the most specific test be used to confirm (rule in) a diagnosis, and the most sensitive test be used to establish that a disease is unlikely (rule out). These rule-in and rule-out concepts can also be characterized by the likelihood ratio (LR). However, previous papers discussed only the case of binary tests and assumed test results already known. METHODS: The author proposes using the 'Kullback-Leibler distance' as a new measure of rule-in/out potential. The Kullback-Leibler distance is an abstract concept arising from statistics and information theory. The author shows that it integrates in a proper way two sources of information--the distribution of test outcomes and the LR function. The index predicts the fate of an average subject before testing. RESULTS: Analysis of real and hypothetical data demonstrates its applications beyond binary tests. It works even when the conventional methods of dichotomization and ROC curve analysis fail. CONCLUSIONS: The Kullback-Leibler distance nicely characterizes the before-test rule-in/out potentials. It offers a new perspective from which to evaluate a diagnostic test. (+info)
Synthesis of polyacrylamides N-substituted with PNA-like oligonucleotide mimics for molecular diagnostic applications.
Two types of oligonucleotide mimics relative to peptide nucleic acids (PNAs) were tested as probes in nucleic acid hybridisation assays based on polyacrylamide technology. One type of mimic oligomers represented a chimera constructed of PNA and phosphono-PNA (pPNA) monomers, and the other one contained pPNA residues alternating with PNA-like monomers on the base of trans -4-hydroxy-L-proline (HypNA). A chemistry providing efficient and specific covalent attachment of these DNA mimics to acrylamide polymers using a convenient approach based on the co-polymerisation of acrylamide and some reactive acrylic acid derivatives with oligomers bearing 5'- or 3'-terminal acrylamide groups has been developed. A comparative study of polyacrylamide conjugates with oligonucleotides and mimic oligomers demonstrated the suitability and high potential of PNA-pPNA and HypNA-pPNA chimeras as sequence-specific probes in capture and detection of target nucleic acid fragments to serve current forms of DNA arrays. (+info)
Effect of a patient's psychiatric history on physicians' estimation of probability of disease.
A questionnaire was mailed to 300 Iowa family physicians to determine the influence of a prior psychiatric history on decision making. The response rate was 77%. Respondents were less likely to believe that a patient had serious illness when presenting with a severe headache or abdominal pain if the patient had a prior history of depression ( P <.05) or prior history of somatic complaints ( P <. 05), compared with a patient with no past history. Respondents were less likely to report that they would order testing for a patient with headache or abdominal pain if the patient had a history of depression ( P <.05, P =.08, respectively) or somatic complaints ( P <.01). Differences in likelihood of ordering tests were not significant after adjusting for differences in estimated probability of disease. We conclude that physicians respond differently to patients with psychiatric illness because of their estimation of pretest probability of disease rather than bias. We conclude that past psychiatric history influences physicians' estimation of disease presence and willingness to order tests. (+info)
From diagnosis to drug taking: staff compliance with guidelines and patient compliance to prescriptions in Burkina Faso.
OBJECTIVE: We studied compliance with guidelines and prescriptions for six steps of the health care process to identify the step with the greatest need for improvement. DESIGN: In a cross-sectional study we used hidden observation in health centres and counting of remaining drugs in home visits. We assessed provider compliance with guidelines for medical history, physical examination, drug choice, and explanation of drug dosing, and patient compliance for drug buying and drug taking. SETTING: The study took place in six rural health centres in Burkina Faso. MAIN OUTCOME MEASURES: We measured unconditional (UPC), conditional (CPC) and accumulated proportions of compliant procedures (APC). UPC determined the proportion of compliant procedures independent from earlier steps. CPC was defined as the proportion of compliant procedures among those which were compliant in all previous steps. APC was the proportion of procedures compliant in all steps including the step concerned. RESULTS: Twenty-three per cent UPC medical history, 27% UPC (CPC = 39%) clinical examination, 59% (83%) drug choice, 22% (40%) explanation of dosing, 71% (75%) drug buying, and 63% (67%) drug taking compliance. Two per cent of the patients had compliant procedures for all steps of the process (APC). CONCLUSION: The majority of patients did not get treatment compliant with guidelines. Diagnosis had the largest need for improvement. UPC, CPC and APC were useful to identify steps with the greatest need for improvement and to assess quantitatively aspects of quality of care. (+info)