Limitations Of Screening Tests Research Articles

Bayesian updating and sequential testing: overcoming inferential limitations of screening tests

BackgroundBayes’ theorem confers inherent limitations on the accuracy of screening tests as a function of disease prevalence. Herein, we establish a mathematical model to determine whether sequential testing with a single test overcomes the aforementioned Bayesian limitations and thus improves the reliability of screening tests.MethodsWe use Bayes’ theorem to derive the positive predictive value equation, and apply the Bayesian updating method to obtain the equation for the positive predictive value (PPV) following repeated testing. We likewise derive the equation which determines the number of iterations of a positive test needed to obtain a desired positive predictive value, represented graphically by the tablecloth function.ResultsFor a given PPV (rho) approaching k, the number of positive test iterations needed given a prevalence of disease (phi) is:n_i =lim _{rho rightarrow k}leftlceil frac{lnleft[ frac{rho (phi -1)}{phi (rho -1)}right] }{lnleft[ frac{a}{1-b}right] }rightrceil qquad qquad (1)where n_i = number of testing iterations necessary to achieve rho, the desired positive predictive value, ln = the natural logarithm, a = sensitivity, b = specificity, phi = disease prevalence/pre-test probability and k = constant.ConclusionsBased on the aforementioned derivation, we provide reference tables for the number of test iterations needed to obtain a rho (phi ) of 50, 75, 95 and 99% as a function of various levels of sensitivity, specificity and disease prevalence/pre-test probability. Clinical validation of these concepts needs to be obtained prior to its widespread application.

ИСПОЛЬЗОВАНИЕ МКФ В РЕАБИЛИТАЦИИ: КЛИНИЧЕСКИЙ СЛУЧАЙ

The article describes a clinical case of a patient with an acute cerebrovascular accident (CVA) at the second stage of medical rehabilitation, conducted by a psychologist as part of a multidisciplinary team. It presents the main concepts and content of the International Classi-fication of Functioning, Disability and Health (ICF). Attention is drawn to a unified language of its application, available to all members of such a multidisciplinary team implementing the process of rehabilitation. The importance of psychological evaluation within the ICF catego-ries for effective interaction between this team’s specialists has been shown. A specific fea-ture of this case was a possibility of using categories belonging to almost all the ICF sections. The purpose of this work is to introduce psychologists to a clinical psychologist’s com-petencies and possibilities of applying the ICF in the rehabilitation of patients with an acute CVA at the second stage of medical rehabilitation. Materials and methods. The article focuses on a clinical case of a female patient with an acute CVA during the early recovery period at the second stage of medical rehabilitation with a description of the dynamics of her psychological status, using the ICF categories. Results. The article provides a list of psychological domains presented in the following ICF sections: "Body Functions", "Activity and Participation", and "Environmental Factors", which can be used by a clinical psychologist within rehabilitation activities. The rehabilitation diagnosis for this patient with an acute CVA in her early recovery period was provided by means of the ICF categories based on her individual characteristics and impairments, and the dynamics of recovery has been revealed. The ICF domains are presented with an indication of the content aspect and the degree of impairment. Discussion of results. The clinical case demonstrates the importance of taking into ac-count personal and environmental factors when describing one’s rehabilitation diagnosis and organizing the rehabilitation process. Applying the ICF categories makes the patient's features and problems clear to all the multidisciplinary team members. The main difficulties of working with the ICF are related to the selection of domains due to the discrepancy between the conceptual apparatus of foreign and domestic psychology. The importance of understanding the semantic component of the domain has been shown. Limitations of screening tests have been noted, and the need to conduct a qualitative analysis of mental disorders within the framework of a personality-oriented approach has been updated. Conclusions. Applying the ICF allows one to maintain a productive interaction with all the members of the multidisciplinary team, describe the patient’s current problems and visually assess the dynamics of recovery. At the same time, its use in the practice of a clinical psychologist requires a specialist to have a deep understanding of the content of the ICF psychological domains and skills to select them for each specific case.

Contributions and Limitations of National Cervical Cancer Screening Program in Korea: A Retrospective Observational Study

The purpose of this study was to evaluate the contributions and limitations of the cervical cancer screening test with accuracy in Korea. This was a retrospective observational study. The study population consisted of all participants who underwent cervical cancer screening test from 2009 to 2014. The data were obtained from National Health Information Database (NHID) which represents medical use records of most Koreans. As the indices for contributions and limitations of the screening test, crude detection rate, incidence rate of interval cancer, sensitivity, specificity, and positive predictive value were used. The crude detection rate of screening test per 100,000 participants increased from 100.7 in 2009 to 102.1 in 2014. The incidence rate of interval cancer per 100,000 negatives decreased from 13.0 in 2009 to 10.2 in 2014. The sensitivities of screening test were 88.7% in 2009 and 91.2% in 2014, and the specificities were 98.5% in 2009 and 97.7% in 2014. The positive predictive value of screening decreased from 6.2% in 2009 to 4.3% in 2014. The Korean national cervical cancer screening program has improved in accuracy and has contributed to detection of early stage of cervical cancer over the years. Along with efforts to promote participation in cancer screening programs, quality control over the screening program should be enhanced.

Tuberculosis in solid organ transplant candidates and recipients: current and future challenges.

Tuberculosis (TB) infection in solid organ transplant recipients poses unique diagnostic and treatment challenges. Recent guidelines for prevention of donor-derived TB and updates on TB diagnostics and treatment in the transplant setting are reviewed as follows. Prevention of donor-derived TB can be optimized by careful screening of donors with risk factors for TB, with effort taken to rule out active TB in the donor, and targeted treatment of recipients. However, transmission may still occur, especially through lung allografts, given limitations of screening tests and treatment strategies. Diagnostics for latent tuberculosis infection are limited in sensitivity and have a relatively low predictive value for development of active TB. Treatment options for latent and active TB carry risks that are still being elucidated in transplant patients, such as a dysregulated inflammatory response manifested by immune reconstitution syndrome. More sensitive diagnostics in deceased donors are needed to quantify the risk of TB transmission and the risk of progression to active tuberculosis in those with latent tuberculosis infection prior to transplant. Novel TB therapies of shorter duration with less toxicity for both latent and active TB will be of great benefit to transplant patients.

CORONARY REVASCULARISATION IN CHRONIC KIDNEY DISEASE PART 1: STABLE CORONARY ARTERY DISEASE

Chronic kidney disease (CKD) is associated with a high burden of coronary artery disease, myocardial infarction and cardiovascular death. Detection and treatment of coronary artery disease in CKD patients has been hampered by the limitations of screening tests, the lack of direct evidence for therapeutic interventions in this specific population, and concerns about therapy-related adverse effects. However, these patients potentially have much to gain from conventional strategies used in the general population. This review summarises the current evidence regarding the treatment of coronary artery disease in patients with CKD, with the focus on coronary revascularisation by percutaneous coronary intervention or coronary artery bypass grafting.

Committee Opinion No. 356: Routine Cancer Screening

Obstetrician-gynecologists serve as primary care physicians for many women. Because the obstetrician-gynecologist may be the only physician providing routine care, clinicians should be able to provide recommendations for routine cancer screenings, including those for nongynecologic cancers. This document summarizes recommendations of the American College of Obstetricians and Gynecologists for routine cancer screening for the average-risk American woman. The obstetrician-gynecologist should discuss both benefits and limitations of screening tests with the patient.

Limitations of screening tests for the detection of Chlamydia trachomatis in asymptomatic adolescent and young adult womenShrier LA, Dean D, Klein E, Harter K, Rice PA. Limitations of screening tests for the detection of Chlamydia trachomatis in asymptomatic adolescent and young adult women. Am J Obstet Gynecol 2004;190:654?62

Limitations of screening tests for the detection of Chlamydia trachomatis in asymptomatic adolescent and young adult womenShrier LA, Dean D, Klein E, Harter K, Rice PA. Limitations of screening tests for the detection of Chlamydia trachomatis in asymptomatic adolescent and young adult women. Am J Obstet Gynecol 2004;190:654?62

Limitations of Screening Tests for the Detection of Chlamydia trachomatis in Asymptomatic Adolescent and Young Adult Women

One hundred sexually active women aged 16 to 25 years who were being seen for a routine gynecologic examination were recruited to participate in this investigation of screening for chlamydial infection in asymptomatic patients. Before clinical examination, the women performed a self-collected screening technique using 2 Dacron swabs, which they inserted approximately 2 inches into their own vagina, swirled, and placed in a transport media for polymerase chain reaction (PCR). They also provided a urine specimen consisting of the first 30 mL of voided urine collected in a sterile container for PCR and ligase chain reaction (LCR). The clinician collected urethral, vaginal, and endocervical swabs, which were cultured and analyzed with PCR, LCR, and nucleic acid amplification tests. Results were available for 139 participants, who had a mean age of 19.1 years and a mean of 10 days since their last sexual encounter. Twenty-two women had a history of chlamydial infection and 8 had a history of other sexually transmitted disease. During clinical examination of these asymptomatic patients, 34% were found to have a vaginal discharge, and 22% had other cervical abnormalities (discharge, mucopus, lesions, friability, inflammation). Chlamydia trachomatis was diagnosed in 30 (22%) women. Among these women, there were 27 (21%) with true C. trachomatis. One hundred twenty-six study subjects had complete results from all 9 clinical tests. Test measures included urethral culture and PCR, self-collected vaginal PCR, clinician-collected vaginal PCR, endocervical culture, PCR, LCR, and urine PCR and LCR. Four patients were positive for all 9 tests, 8 had a single positive test (confirmed by nested PCR testing), and 15 had between 2 and 8 positive results. The characteristics of various tests and different collection sites are shown in Table 1. Both PCR and LCR yielded more positive results than culture. They were also more sensitive than culture, although some LCR had a lower specificity than either of the other tests. The positive and negative predictive values were high for all tests. When 2 tests were combined, urine LCR plus endocervical LCR proved the most sensitive but had a somewhat lower specificity than other combination strategies.

A midwife's role in prenatal screening

As technology in the field of investigative medicine is advancing rapidly, a growing number of expectant parents are choosing to undertake prenatal screening. However, as much of the literature surrounding this subject highlights, the processes, implications, limitations and results of this testing are still poorly understood by the majority of expectant parents. As informed choice and consent are of such importance in health care today, the distinct lack of knowledge in this area suggests that there is a further need for pre-test information and counselling, particularly as serum screening tests are performed on an opt-in basis. The role of the midwife has now been expanded to include genetic counselling. Therefore midwives must be fully informed about all areas of serum screening in order to impart this information to the women in their care. It is also essential for all women to understand the limitations of screening tests.

Diagnosis of Canine Hyperadrenocorticism

Diagnosis of canine hyperadrenocorticism can only be made when a suspicion of the disorder persists after completion of a thorough history and physical examination. The first diagnostic testing steps include a complete blood count, serum biochemical tests, and urinalysis with urine culture. Radiography or ultrasonography may also be necessary, depending on physical findings. Screening tests are next applied to support or exclude the clinical diagnosis of hyperadrenocorticism. After the diagnosis has been made, discrimination tests are applied to determine whether the cause is pituitary or adrenal. The limitations of screening tests, particularly in the presence of nonadrenal diseases, cannot be overemphasized. We recommend that neither screening tests nor discrimination tests for hyperadrenocorticism be used in dogs with concurrent nonadrenal disease.

Performance Characteristics of Screening Tests

The limitations of screening tests in accurately detecting disease are explored. Special issues in the characteristics of screening tests, such as the use of tests in combination and repeat testing, are considered. Studies such as the Mayo Lung Project and the Health Insurance Plan study provide clinical illustrations of theoretical points.