Negative Diagnostic Test Research Articles

Rapid clinical diagnosis in fatal swine influenza (H1N1) pneumonia in an adult with negative rapid influenza diagnostic tests (RIDTs): Diagnostic swine influenza triad

BackgroundThe “herald wave” of the H1N1 pandemic spread from Mexico to the United States in spring 2009. Initially, the epicenter of H1N1 in the United States was in the New York area. Our hospital, like others, was inundated with large numbers of patients who presented at the Emergency Department (ED) with influenza-like illnesses (ILIs) for swine influenza testing and evaluation.MethodsThe Winthrop-University Hospital ED used rapid influenza (QuickVue A/B) tests to screen for H1N1 infection. Patients who were rapid influenza A test-positive were also reverse transcription-polymerase chain reaction (RT-PCR) positive for H1N1. In our ED, 30% of patients with ILIs and possible H1N1 pneumonia had negative rapid influenza A screening tests. Because H1N1 RT-PCR testing was restricted, there was no laboratory test to confirm or rule out H1N1. Other rapid influenza diagnostic tests (RIDTs), e.g., the respiratory fluorescent antibody (FA) viral panel test, were used to identify H1N1 patients with negative RIDTs.ResultsUnfortunately, there was not a good correlation between RIDT results and RT-PCR results. There was a critical need to develop a clinical syndromic approach for diagnosing hospitalized adults with probable H1N1 pneumonia with negative RIDTs. Early in the pandemic, the Winthrop-University Hospital Infectious Disease Division developed a diagnostic weighted point score system to diagnose H1N1 pneumonia clinically in RIDT-negative adults. The point score system worked well, but was time-consuming. As the “herald wave” of the pandemic progressed, our ED staff needed a rapid, simplified method to diagnose probable H1N1 pneumonia in hospitalized adults with negative RIDTs. A rapid and simplified diagnosis was based on the diagnostic weighted point score system, which we simplified into a triad of key, nonspecific laboratory indicators. In adults hospitalized with an ILI, a fever >102°F with severe myalgias, and a chest x-ray without focal segmental/lobar infiltrates, the presence of three indicators, i.e., otherwise unexplained relative lymphopenia, elevated serum transaminases, and an elevated creatinine phosphokinase, constituted the diagnostic swine influenza triad. The Infectious Disease Division's diagnostic swine flu triad was used effectively as the pandemic progressed, and was not only useful in correctly diagnosing probable H1N1 pneumonia in hospitalized adults with negative RIDTs, but was also in ruling out mimics of swine influenza, e.g., exacerbations of chronic bronchitis, asthma, or congestive heart failure, as well as bacterial community-acquired pneumonias (CAPs), e.g., legionnaire's disease.ConclusionClinicians can use the Winthrop-University Hospital Infectious Disease Division's Diagnostic swine influenza triad to make a rapid clinical diagnosis of probable H1N1 pneumonia in hospitalized adult patients with negative RIDTs.

H1N1 Influenza: Contact Investigation Burden because of Failure to Institute Influenza Precautions in Patients with Negative Rapid Influenza Diagnostic Test Results

H1N1 Influenza: Contact Investigation Burden because of Failure to Institute Influenza Precautions in Patients with Negative Rapid Influenza Diagnostic Test Results

Winthrop-University Hospital Infectious Disease Division's swine influenza (H1N1) pneumonia diagnostic weighted point score system for hospitalized adults with influenza-like illnesses (ILIs) and negative rapid influenza diagnostic tests (RIDTs)

BackgroundIn spring 2009, a novel strain of influenza A originating in Veracruz, Mexico, quickly spread to the United States and throughout the world. This influenza A virus was the product of gene reassortment of 4 different genetic elements: human influenza, swine influenza, avian influenza, and Eurasian swine influenza. In the United States, New York was the epicenter of the swine influenza (H1N1) pandemic. Hospital emergency departments (EDs) were inundated with patients with influenza-like illnesses (ILIs) requesting screening for H1N1. Our ED screening, as well as many others, used a rapid screening test for influenza A (QuickVue A/B) because H1N1 was a variant of influenza A. The definitive laboratory test i.e., RT-PCR for H1N1 was developed by the Centers for Disease Control (Atlanta, GA) and subsequently distributed to health departments. Because of the extraordinary volume of test requests, health authorities restricted reverse transcription polymerase chain reaction (RT-PCR) testing. Hence most EDs, including our own, were dependent on rapid influenza diagnostic tests (RIDTs) for swine influenza. A positive rapid influenza A test was usually predictive of RT-PCR H1N1 positivity, but the rapid influenza A screening test (QuickVue A/B) was associated with 30% false negatives. The inability to rely on RIDTs for H1N1 diagnosis resulted in underdiagnosing H1N1. Confronted with adults admitted with ILIs, negative RIDTs, and restricted RT-PCR testing, there was a critical need to develop clinical criteria to diagnose probable swine influenza H1N1 pneumonia.MethodsDuring the pandemic, the Infectious Disease Division at Winthrop-University Hospital developed clinical criteria for adult admitted patients with ILIs and negative RIDTs. Similar to the one developed for the clinical diagnosis of legionnaire's disease. The Winthrop-University Hospital Infectious Disease Division's diagnostic weighted point score system for swine influenza H1N1 pneumonia is based on key clinical and laboratory features.ResultsDuring the “herald” wave of the swine influenza H1N1 pandemic, the diagnostic weighted point score system accurately identified probable swine influenza H1N1 pneumonia and accurately differentiated swine influenza H1N1 pneumonia from ILIs and other viral and bacterial community-acquired pneumonias.ConclusionIn hospitalized adults with ILIs and negative RIDTs, the diagnostic weighted diagnostic point score system, may be used to make a presumptive clinical diagnosis of swine influenza H1N1 pneumonia.

Soy allergy in perspective

The purpose of this paper is to review and discuss studies on soy allergy. In Central Europe soy is a clinically relevant birch pollen-related allergenic food. Crossreaction is mediated by a Bet v 1 homologous protein, Gly m 4. Additionally, birch pollen allergic patients might acquire through Bet v 1 sensitization allergies to mungbean or peanut, in which Vig r 1 and Ara h 8 are the main cross-reactive allergens. Threshold doses in soy allergic individuals range from 10 mg to 50 g of soy and are more than one order of magnitude higher than in peanut allergy. No evidence was found for increased allergenicity of genetically modified soybeans. In Europe, both primary and pollen-related food allergy exist. The diagnosis of legume allergy in birch pollen-sensitized patients should not be excluded on a negative IgE testing to legume extracts. Bet v 1 related allergens are often underrepresented in extracts. Gly m 4 from soy and Ara h 8 from peanut are nowadays commercially available and are recommended in birch pollen allergic patients with suspicion of soy or peanut allergy, but negative extract-based diagnostic tests to screen for IgE specific to these recombinant allergens.

Are patients with positive screening but negative diagnostic test for gestational diabetes under risk for adverse pregnancy outcome?

Our aim was to determine the obstetrics outcomes of patients with positive 1-h glucose challenge test (GCT), but negative diagnostic test for gestational diabetes. Pregnancy records of 409 pregnants were reviewed. Patients were screened for gestational diabetes mellitus (GDM) with one-hour 50 g glucose challenge test (GCT) at 24-28 weeks of gestation. Patients with glucose challenge tests values > or = 130 mg/dL were refered for the 3 h, 100-g oral glucose tolerance test (OGTT). Positive GCT but negative for OGTT group (Group A) were compared retrospectively with the group of negative GCT (Group B) for obstetrics outcomes. GDM and impared glucose tolerance (IGT) were diagnosed in 33 (7.6%) and 46 (10.5%) patients, respectively. We identified 141 (34.4%) patients with positive GCT but negative for OGTT (Group A) and 189 (46.2%) patients with negative GCT (Group B). Gestational weight gain, polyhydramnios, family history of diabetes mellitus were significantly higher in group A than group B (P < 0.05). Prevalance of preterm labor, hypertension, cesarean delivery, mean birthweight, proportion of babies admitted to neonatal intensive care unit were similar in both groups. There are some differences for pregnancy outcomes between pregnants with positive GCT but negative for OGTT and negative GCT. These patients should be followed up carefully during the antepartum and intrapartum period.

JAK2 V617F in Patients with Idiopathic Thromboses in Common Locations.

Background: Polycythemia vera and essential thrombocytosis, two of the myeloproliferative disorders (MPD) often characterized by the recurrent somatic missense mutation JAK2 V617F, are associated with an increased risk of arterial and venous thrombosis. Although recent anecdotal reports have suggested the possibility of latent MPDs by finding JAK2 mutations in patients with abdominal venous thromboses (AVT), the usefulness of routine JAK2 V617F testing has not been assessed in a cohort of general hospital patients with idiopathic thromboses in common locations.Methods: To assess the utility of JAK2 V617F testing in patients undergoing thrombophilia workup, we identified all patients with negative molecular diagnostic tests for the Factor V Leiden (FVL) mutation and the prothrombin gene mutation (G20210A) over the course of one year at the Brigham and Women's Hospital. We then determined, by medical record review, the nature of the thrombotic events for which they were being evaluated, and tested their nucleated white blood cell DNA for the JAK2 V617F mutation using the amplification refractory mutation system (ARMS)-PCR assay (which has a lower limit of detection of 5% mutant alleles).Results: From Februrary 2006 to February 2007, 111 patients had negative tests for both FVL and G20210A. Of these, our chart review revealed that 65 had documented thromboses without a history of malignancy or MPD. None of these were found to have the JAK2 V617F mutation. Laboratory hypercoaguability studies for thrombosis by type (from medical record review) were as follows:Protein C deficiency (%)Protein S deficiency (%)Anti-thrombin III deficiency (%)Antiphospholipid Abs (%)Elevated homocysteine (%)JAK2 V617 mutation (%)None (%)CVA/Stroke (n=10)0200100070DVT/PE (n=45)11202413060AVT (n=6)33330017033Other Arterial Thrombosis (n=4)0250025050In terms of clinical risk factors, 27.6% of patients with documented thromboses had had surgery within the prior month, 26.2% were current smokers, and 31.4% of female patients were either pregnant or taking oral contraceptives. 29.2% of all patients had no clinical or laboratory thrombophilic risk factors.Conclusions: About two-thirds of our general hospital patients with thrombosis and negative tests for FVL and G20210A had another underlying thrombophilic risk factor. Adding JAK2 V617F mutation testing as a routine component of the thrombophilia diagnostic workup is not recommended, as it is unlikely to reveal evidence of a putative latent MPD.

Improved Diagnostic Testing and Malaria Treatment Practices in Zambia

Improving the accuracy of malaria diagnosis with rapid antigen-detection diagnostic tests (RDTs) has been proposed as an approach for reducing overtreatment of malaria in the current era of widespread implementation of artemisinin-based combination therapy in sub-Saharan Africa. To assess the association between use of microscopy and RDT and the prescription of antimalarials. Cross-sectional, cluster sample survey, carried out between March and May 2006, of all outpatients treated during 1 working day at government and mission health facilities in 4 sentinel districts in Zambia. Proportions of patients undergoing malaria diagnostic procedures and receiving antimalarial treatment. Seventeen percent of the 104 health facilities surveyed had functional microscopy, 63% had RDTs available, and 73% had 1 or more diagnostics available. Of patients with fever (suspected malaria), 27.8% (95% confidence interval [CI], 13.1%-42.5%) treated in health facilities with malaria diagnostics were tested and 44.6% had positive test results. Of patients with negative blood smear results, 58.4% (95% CI, 36.7%-80.2%) were prescribed an antimalaria drug, as were 35.5% (95% CI, 16.0%-55.0%) of those with a negative RDT result. Of patients with fever who did not have diagnostic tests done, 65.9% were also prescribed antimalarials. In facilities with artemether-lumefantrine in stock, this antimalarial was prescribed to a large proportion of febrile patients with a positive diagnostic test result (blood smear, 75.0% [95% CI, 51.7%-98.3%]; RDT, 70.4% [95% CI, 39.3%-100.0%]), but also to some of those with a negative diagnostic test result (blood smear, 30.4% [95% CI, 8.0%-52. 9%]; RDT, 26.7% [95% CI, 5.7%-47.7%]). Despite efforts to expand the provision of malaria diagnostics in Zambia, they continue to be underused and patients with negative test results frequently receive antimalarials. Provision of new tools to reduce inappropriate use of new expensive antimalarial treatments must be accompanied by a major change in clinical treatment of patients presenting with fever but lacking evidence of malaria infection.

Local IgE production and positive nasal provocation test in patients with persistent nonallergic rhinitis

Allergic rhinitis is an IgE-mediated inflammatory disease of the nasal mucosa, which is usually diagnosed by typical symptoms, positive skin tests, and/or serum specific IgE antibodies to allergens. Despite suggestive symptoms of allergic rhinitis, some patients have a negative diagnostic test for atopy. To evaluate in the nose the inflammatory response, specific IgE to Dermatophagoides pteronyssinus (DP), and the response to a nasal allergen provocation test with DP (NAPT-DP), in patients with persistent nonallergic rhinitis (PNAR) compared with patients with persistent allergic rhinitis (PAR) and healthy controls. Fifty patients with PNAR, 30 with PAR to DP, and 30 healthy controls were studied by determining the nasal leukocyte-lymphocyte phenotype by flow cytometry (CD16, CD8, CD4, CD33, CD3, and CD45), nasal eosinophil cationic protein (ECP), albumin, total and specific IgE to DP, and NAPT-DP. The PNAR patients showed a similar leukocyte-lymphocyte phenotype in nasal lavage to the PAR patients and was different to the healthy controls. Within the PNAR group, 54% showed a positive NAPT-DP, with 22% of these having nasal specific IgE to DP. These data support the hypothesis that in persistent nonallergic rhinitis some patients may have local inflammation, nasal IgE production, and a positive response to a nasal allergen provocation test despite no evidence of systemic atopy. Further research is needed to evaluate the influence of other perennial allergens and/or immunologic mechanisms. The local production of IgE antibodies without systemic detection is a condition that should be considered in patients with PNAR.

Rapid diagnostic tests compared with malaria microscopy for guiding outpatient treatment of febrile illness in Tanzania: randomised trial

Objective To compare rapid diagnostic tests (RDTs) for malaria with routine microscopy in guiding treatment decisions for febrile patients.Design Randomised trial.Setting Outpatient departments in northeast Tanzania at varying levels of...

Diagnosis of ectopic ureter as a cause of urinary incontinence

Introduction and objective Female pediatric patients with continuous drip incontinence present a diagnostic challenge. At times, these symptoms may be due to an ectopic ureter inserting below the external sphincter. The evaluation may consist an ultrasound and voiding cystourethrogram (VCUG), but these may not be diagnostic and further evaluation may be necessary. We reviewed our experience with imaging modalities used to make the diagnosis of ureteral ectopia. Methods We reviewed the records of 24 female patients with incontinence after toilet training or other symptoms caused by ureteral ectopia. We focused on the initial imaging methods, the modality providing the definitive diagnosis, and outcome. Results Twenty-four patients were identified with an ectopic ureter. Two patients had bilateral ectopia for a total of 26 ectopic ureters. Of the 24 patients, 19 initially had negative diagnostic tests. These combined tests consisted of 15 intravenous pyelograms (IVPs), 18 VCUGs, 14 ultrasound, five cystoscopies, one nuclear VCUG and one MRI. Two patients underwent computed tomography (CT) as the primary test revealing an ectopic system. Of the 26 ectopic ureters, the diagnosis was made by CT scan in 13, IVP in five, cystoscopy in six, and ultrasound in one. One ectopic ureter was identified by exploration. In no cases did a CT scan fail to identify an ectopic system. Conclusion Patients with an ectopic ureter often will have no abnormality on initial imaging studies. Our experience has shown that a CT scan with delayed contrast is the most sensitive, economic and readily available test for diagnosing ecoptic ureters and renal systems.

SMN1dosage analysis in spinal muscular atrophy from India

BackgroundSpinal muscular atrophy (SMA) represents the second most common fatal autosomal recessive disorder after cystic fibrosis. Due to the high carrier frequency, the burden of this genetic disorder is very heavy in developing countries like India. As there is no cure or effective treatment, genetic counseling becomes very important in disease management. SMN1 dosage analysis results can be utilized for identifying carriers before offering prenatal diagnosis in the context of genetic counseling.MethodsIn the present study we analyzed the carrier status of parents and sibs of proven SMA patients. In addition, SMN1 copy number was determined in suspected SMA patients and parents of children with a clinical diagnosis of SMA.Resultswenty nine DNA samples were analyzed by quantitative PCR to determine the number of SMN1 gene copies present, and 17 of these were found to have one SMN1 gene copy. The parents of confirmed SMA patients were found to be obligate carriers of the disease. Dosage analysis was useful in ruling out clinical suspicion of SMA in four patients. In a family with history of a deceased floppy infant and two abortions, both parents were found to be carriers of SMA and prenatal diagnosis could be offered in future pregnancies.ConclusionSMN1 copy number analysis is an important parameter for identification of couples at risk for having a child affected with SMA and reduces unwarranted prenatal diagnosis for SMA. The dosage analysis is also useful for the counseling of clinically suspected SMA with a negative diagnostic SMA test.

Sensitivity, specificity and other diagnostic measures with multiple sites per unit

Medical researchers often study the performance of diagnostic tools. The performance of the diagnostic tool is evaluated by calculating sensitivity, specificity and similar measures. Sensitivity is defined as the probability of a positive diagnostic test in a patient with the illness or injury for which the test serves as a diagnostic tool. Specificity is the probability of a negative diagnostic test in a patient free of the disease or injury. For some conditions, the test is applied to several anatomic locations or at different times in a patient and each test can be positive or negative. The findings of the tests performed on the same patient are correlated and any summary measure should account for this correlation. We propose a summary measure for the subject that combines the results from all tests performed on the same patient while accounting for the correlation. The measure is easily calculated and requires no specific statistical software. We also provide an estimate of the standard error and confidence intervals. The method is illustrated with a study, conducted at the University of California, Davis School of Medicine, of the sensitivity of magnetic resonance (MR) imaging and plain film (PF) radiography in detecting injuries in the cervical spine, such as fractures and soft tissue injuries.

Persistence of elevated rabies prevention costs following post-epizootic declines in rates of rabies among raccoons ( Procyon lotor)

Determining the benefits to cost relationships among different approaches to rabies control and prevention has been hindered by the inherent temporal variability in the dynamics of disease among wildlife reservoir hosts and a tangible and objective measure of the cost of rabies prevention. A major and unavoidable component of rabies prevention programs involves diagnostic testing of animals and the subsequent initiation of appropriate public health responses. The unit cost per negative and positive diagnostic test outcome can be reasonably estimated. This metric when linked to methodologies subdividing the epizootic process into distinct temporal stages provided the requisite detail to estimate benefits derived from rabies control strategies. Oral rabies vaccine (ORV), for prevention of the raccoon-associated variant of rabies, has been distributed in Ohio and adjoining states in an effort to develop an immune barrier to the westward spread of epizootic raccoon rabies. The costs of ORV delivery have been quantified. Herein, the cost structures required to assess the benefits accrued by prevention were developed. A regression model was developed effectively predicting ( r 2 = 0.70) the total number of rabies diagnostic tests performed by 53 counties in five northeastern (NE) states from 1992 to 2001. Five temporal stages sufficed to capture the range of variability in the raccoon rabies epizootic process. Unit costs, dollars per diagnostic test outcome, were calculated for negative and positive results from published reports. Ohio counties were matched to NE counties based on similar socioeconomic characters. A “pseudo-epizootic” of raccoon rabies was introduced into Ohio and the costs savings from ORV were derived as the excess costs imposed by epizootic spread throughout the state. At 46 km/year (range modeled, 30–60 km/year), the pseudo epizootic spread, and reached the enzootic stage, in all Ohio counties by year 13 (range modeled, 11–17 years). Cumulative excess costs for Ohio ranged between $11 and $21 million; counties of low socioeconomic status experienced the greatest relative excess costs. The costs for rabies prevention activities reached apices during the epizootic stage of raccoon rabies (2.7–10.8 times baseline) an unforeseen finding indicated elevated costs persisted (1.7–7.2 times baseline) into the enzootic stage.

Venous Thromboembolism During Pregnancy: Clinical Suspicion Warrants Evaluation

To determine the incidence, signs, symptoms and clinical outcomes of venous thromboembolism (VTE) during pregnancy.A retrospective review was conducted from 1997 to 2001 including women with a diagnosis or suspicion of VTE during pregnancy. Demographics and clinical characteristics of patients with a suspicion for VTE were reviewed.Of 70 patients assessed for evidence of a VTE, 25.7% (n = 18) had confirmatory diagnostic testing. There was no difference in the clinical signs or symptoms between groups with a pulmonary embolism (PE) compared to those without a PE. For those patients with negative diagnostic testing (n = 52), an alternative diagnosis was confirmed in 55.8%. Of the patients with positive diagnostic testing, 30% had a concurrent condition contributing to their pulmonary symptoms.Lack of definitive signs and symptoms of thromboembolic disease during pregnancy warrants complete evaluation of patients clinically suspected of having VTE.

SARS — Looking Back over the First 100 Days

Each winter, a number of surveillance networks are put in place to detect unusual outbreaks of severe respiratory disease. Last winter, although there had been some minor activity, nothing serious came up until late February 2003, when Dr. Carlo Urbani alerted the World Health Organization (WHO) that there was a novel form of severe pneumonia at a hospital in Hanoi, Vietnam. The pneumonia had a peculiar hallmark: health care workers were being stricken at an alarming rate. With this key observation and many negative diagnostic tests for known pathogens, it became clear that we had a new disease, severe acute . . .

The benefit of negative tests in non-ulcer dyspepsia.

Negative diagnostic tests are usually evaluated by their ability to advance a diagnostic search, or they are considered redundant expenditures in establishing a definitive diagnosis. It has remained difficult to assess their benefit in terms of their own merit and the reassurance that they provide to a patient. The aim of the present study is to develop a mathematical model for quantifying the impact of diagnostic tests on a patient's health-related quality of life (HRQL). An influence diagram is used to model how non-ulcer dyspepsia (NUD) and its medical care affect HRQL. Diagnostic tests and medical therapy benefit HRQL by alleviating fear of disease and NUD symptoms. Medical care can also adversely affect HRQL, lead to expenses in time and money, and compromise a patient's sense of autonomy. HRQL is modeled as the focal point of multiple influences detracting from its value. Negative diagnostic tests can improve HRQL in NUD. The improvement of HRQL by diagnostic tests depends on a multitude of individual influences and the interactions between them, such as the severity of NUD symptoms andfear of disease, as well as the impact of medical care itself on HRQL. If a patient harbors a strong fear of serious disease or cancer, more extensive testing is likely to improve the patient's well-being and appears a worthwhile endeavor. Other patients, however, would be served perfectly well by empirical therapy only. For the vast majority of subjects with NUD who never seek medical advice, the unpleasantness of the disease itself does not outweigh the anticipated downside of obtaining medical care. The analysis illustrates the applicability of the influence diagram in modeling disease behavior. This method helps to assess the benefit of negative tests beyond their means of generating information.

Elementary school-age children's capacity to choose positive diagnostic and negative diagnostic tests.

Two experiments involving 72 elementary school-age children (mean age = 10 years, 3 months, range = 9,4-11,8) and 72 adults compared the ability of participants to choose positive and negative diagnostic tests over positive and negative nondiagnostic tests. Both experiments employed novel test materials, which resolved any issues regarding the effects of context on test strategy employment. In Experiment 1, both children and adults were significantly more likely to prefer positive diagnostic tests over positive nondiagnostic tests; however, only adults demonstrated a significant preference for negative diagnostic tests over positive nondiagnostic ones. In Experiment 2, both children and adults were more likely to choose negative diagnostic tests over negative nondiagnostic tests, demonstrating that despite a strong positive test bias, children could reason diagnostically in selecting among negative tests in cases in which only negative test choices were available.

The Benefit of Negative Tests in Non-Ulcer Dyspepsia

Objectives. Negative diagnostic tests are usually evaluated by their ability to advance a diagnostic search, or they are considered redundant expenditures in establishing a definitive diagnosis. It has remained difficult to assess their benefit in terms of their own merit and the reassurance that they provide to a patient. The aim of the present study is to develop a mathematical model for quantifying the impact of diagnostic tests on a patient’s health-related quality of life (HRQL).Methods. An influence diagram is used to model how non-ulcer dyspepsia (NUD) and its medical care affect HRQL. Diagnostic tests and medical therapy benefit HRQL by alleviating fear of disease and NUD symptoms. Medical care can also adversely affect HRQL, lead to expenses in time and money, and compromise a patient’s sense of autonomy. HRQL is modeled as the focal point of multiple influences detracting from its value.Results. Negative diagnostic tests can improve HRQL in NUD. The improvement of HRQL by diagnostic tests depends on a multitude of individual influences and the interactions between them, such as the severity of NUD symptoms and fear of disease, as well as the impact of medical care itself on HRQL. If a patient harbors a strong fear of serious disease or cancer, more extensive testing is likely to improve the patient’s well-being and appears a worthwhile endeavor. Other patients, however, would be served perfectly well by empirical therapy only. For the vast majority of subjects with NUD who never seek medical advice, the unpleasantness of the disease itself does not outweigh the anticipated downside of obtaining medical care.Conclusion. The analysis illustrates the applicability of the influence diagram in modeling disease behavior. This method helps to assess the benefit of negative tests beyond their means of generating information.

Rational testing of the HIV-exposed infant.

The objectives of this study were 1) to evaluate testing regimens of human immunodeficiency virus (HIV)-exposed infants and 2) to determine optimal methods of follow-up by enzyme-linked immunosorbent assay (ELISA) testing. We reviewed the results from 742 HIV-exposed infants in the state of North Carolina; 2474 samples were tested for HIV by DNA polymerase chain reaction (PCR) at the University of North Carolina Retrovirology Core Laboratory. We then reviewed the utility and costs of ELISA testing of all HIV-exposed infants who were seen at the Duke University Pediatric Infectious Disease Clinic between January 1, 1993, and May 5, 1998. We used likelihood ratios to model probability of HIV infection given 3 negative DNA (PCR) tests and to provide recommendations on the use of ELISA follow-up. The overall sensitivity of the DNA PCR was 87.1%, and its specificity was 99.9%. We evaluated 224 HIV-exposed infants who were seen at Duke University and who had at least 3 negative diagnostic tests using either DNA PCR tests or HIV blood cultures. All 178 infants who subsequently underwent ELISA testing ultimately demonstrated seroreversion. The Duke University Pediatric Infectious Disease Clinic transferred the care of 65 patients to primary care physicians before ELISA testing and retained the care of the remaining 159 patients. Children who remained in Duke's care were more likely to have documentation of seroreversion (158 of 159 vs 20 of 65). We reviewed costs of travel, physician appointment, and HIV antibody testing in a tertiary care setting. Given 3 negative PCR tests, the expected cost per case of HIV detected by a positive ELISA assay is $23.8 million. Documentation of seroreversion in this cohort was nearly complete in the multidisciplinary subspecialty clinic but not when such responsibility was left to the primary care physician. Given the low probability of disease in patients who have had 3 negative PCR tests, documentation of a negative ELISA may not be an appropriate use of medical resources.

Anwendung eines sensitiven Verfahrens zur Diagnose des Gestationsdiabetes. Metabolische und klinische Ergebnisse

Der unbehandelte (oder unerkannte) Gestationsdiabetes (GD) ist mit einer signifikanten perinatalen Morbidität und Mortalität behaftet. Es gibt jedoch derzeit keine international einheitlichen Richtlinien zur Diagnose des GD. Ziel der vorliegenden Arbeit ist die Evaluierung einer sensitiven diagnostischen Strategie zur Erfassung des GD.