Touching all the bases in diagnostic test assessment
Article Abstract:
Methods for evaluating new diagnostic laboratory tests have never been standardized, although several articles have proposed guidelines for assessing diagnostic tests. A recent study evaluated noninvasive tests as predictors of bone marrow iron stores in the elderly, and successfully illustrated the principles of laboratory test evaluation. The initial step in evaluating a diagnostic test is to define the clinical problem, which in this study was the diagnosis of iron deficiency in the elderly. The next step, the characterization of the study population, is often associated with spectrum problems, defined as the analysis of an inappropriate sample, as well as bias, the incomplete verification of the study population by a definitive diagnostic procedure. The ideal study population consists of an entire group that is geographically and demographically uniform. In this study, 259 patients over the age of 65 years were seen at an urban hospital and underwent bone marrow aspiration, a procedure for sampling bone marrow tissue. The third step in evaluating diagnostic tests is the analysis of the results. The estimation of specificity and sensitivity may be of limited value, whereas receiver operating characteristic (ROC) curves provide a measure of the discrimination power of a diagnostic test. In the iron deficiency study, data were analyzed by ROC curves and likelihood ratios, and the findings were consistent with those of other studies. Therefore, this iron deficiency study has illustrated the appropriate procedures for assessing diagnostic tests. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Medicine
Subject: Health care industry
ISSN: 0002-9343
Year: 1990
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Clinical deterioration in patients with idiopathic pulmonary fibrosis: causes and assessment
Article Abstract:
Idiopathic pulmonary fibrosis is an interstitial lung disease, usually occurring in middle-aged individuals. Normal lung tissue is replaced by fibrous connective tissue, resulting in loss of elasticity of the lung. Frequently, the symptoms are shortness of breath on exertion, and occasionally, an associated dry cough. Examination usually reveals crackles in the lungs, and a diffuse interstitial infiltrate is seen on chest X-rays. Pulmonary function tests reveal a restrictive lung pattern with reduced lung volume. Patients inevitably have decreased function that is most often due to progression of the fibrosis. The cause of this deterioration is not clear. Often, the progression of the disease is difficult to distinguish from disease complications and complications of treatment. Respiratory failure is the most frequent cause of death in these patients (38.7 percent); other causes of death include heart failure (14.4 percent), lung cancer (10.4 percent), heart disease (9.5 percent), infection (6.5 percent), and pulmonary embolism (3.4 percent). Non-fatal complications can include collapsed lung, side effects of steroid treatment, muscle abnormalities, and suppression of the immune system as a result of treatment. Assessment of the progression of the disease and its associated complications is usually carried out by chest X-rays; lung function tests, including exercise testing; bronchoalveolar lavage to extract fluid and cell samples from the lung; and gallium lung scanning. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Medicine
Subject: Health care industry
ISSN: 0002-9343
Year: 1990
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Liability issues and assessment of decision-making capability in nursing home patients
Article Abstract:
Health care providers are constantly aware of legal liability, and consequently try to minimize the risks of harm to the patient and the associated risks of legal and financial loss to themselves. This approach may adversely affect the autonomy and well-being of the patient, and may result a in waste of patient and economic resources. This aversion of risk may also result in a tendency to rely on the relatives of elderly nursing home residents for decisions. Physicians and nurses tend to view relatives of the patient, rather than the patient, as potential malpractice plaintiffs. Hence, if there is any question about the decision-making capacity of the patient, the medical staff often seeks the advice of the patient's family concerning decisions. Physicians may be motivated by professional bias, such as the belief that old, frail nursing home patients are unable to make decisions. They may also be influenced by administrative convenience; it may be more efficient to deal with an articulate relative rather than an impaired older nursing home patient. These and other issues concerning liability and the decision-making capability of nursing home patients are discussed. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Medicine
Subject: Health care industry
ISSN: 0002-9343
Year: 1990
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